THE ENVIRONMENTAL HEALTH CRITERIA SERIES

Acetonitrile (No. 154, 1993) 1,2-Dichloroethane (No. 62, 1987) Acrolein (No. 127, 1991) 2,4-Dichlorophenoxyacetic acid (2,4-D) (No 29, Acrylamide (No 49, 1985) 1984) Acrylonitrile (No. 28, 1983) 2,4-Dichlorophenoxyacetic acid - environmental Aged population, principles for evaluating the aspects (No. 84, 1989) effects of chemicals (No. 144, 1992) 1,3-Dichloropropene, 1,2-dichloropropane and Aldicarb (No. 121, 1991) mixtures (No. 146, 1993) Aldrin and dieldrin (No. 91, 1989) Dichlorvos (No 79, 1988) Allethrlns (No. 87, 1989) Diethylhexyl phthalate (No. 131, 1992) Amitrole (No. 158, 1994) Dimethoate (No. 90, 1989) Ammonia (No. 54, 1986) Dimethylformamide (No. 114, 1991) Arsenic (No. 18, 1981) Dimethyl sulfate (No. 48, 1985) Asbestos and other natural mineral fibres Diseases of suspected chemical etiology and (No. 53, 1986) their prevention, principles of studies on Barium (No. 107, 1990) (No. 72, 1987) Benomyl (No 148, 1993) Dithiocarbamate pesticides, ethylenethiourea, and Benzene (No. 150, 1993) propylenethiourea: a general introduction Beryllium (No. 106, 1990) (No. 78, 1988) Biomarkers and risk assessment· concepts Electromagnetic fields (No. 137, 1992) and principles (No. 155, 1993) Endosulfan (No. 40, 1984) Biotoxins, aquatic (marine and freshwater) Endrin (No 130, 1992) (No. 37, 1984) Environmental epidemiology, guidelines on Brominated dlphenylethers (No. 162, 1994) studies in (No. 27, 1983) Butanols - four Isomers (No. 65, 1987) Epichlorohydrin (No 33, 1984) Cadmium (No. 134, 1992) Ethylene oxide (No 55, 1985) Cadmium - environmental aspects (No. 135, 1992) Extremely low frequency (ELF) fields (No 35, Camphechlor (No. 45, 1984) 1984) Carbamate pesticides. a general introduction Fenitrothion (No 133, 1992) (No. 64, 1986) Fenvalerate (No 95, 1990) Carbaryl (No. 153, 1994) Fluorine and nuorides (No. 36, 1984) Carbendazim (No. 149, 1993) Food additives and contaminants in food, Carbon disulfide (No. 10, 1979) principles for the safety assessment of Carbon monoxide (No 13, 1979) (No 70, 1987) Carcinogens, summary report on the evaluation Formaldehyde (No. 89, 1989) of short-term in vitro tests (No. 47, 1985) Genetic effects In human populations, Carcinogens, summary report on the evaluation guidelines for the study of (No. 46, 1985) of short-term in vivo tests (No 109, 1990) Glyphosate (No. 159, 1994) Chlordane (No. 34, 1984) Heptachlor (No 38, 1984) Chlordecone (No. 43, 1984) Hexachlorobutadiene (No 156, 1994) Chlorine and hydrogen chloride (No 21, 1982) Alpha- and beta-hexachlorocyclohexanes Chlorobenzenes other than hexachlorobenzene (No. 123, 1991) (No. 128, 1991) Hexachlorocyclopentadiene (No. 120, 1991) Chloronuorocarbons, fully halogenated (No. 113, n-Hexane (No. 122, 1991) 1990) Hydrazine (No. 68, 1987) Chloronuorocarbons, partially halogenated Hydrogen sulfide (No 19, 1981) (ethane derivatives) (No. 139, 1992) Hydroqulnone (No. 157, 1994) (methane derivatives) (No. 126, 1991) Infancy and ear1y childhood, principles for Chlorophenols (No 93, 1989) evaluating health risks from chemicals Chromium (No 61, 1988) during (No. 59, 1986) Cyhalothrin (No 99, 1990) lsobenzan (No. 129, 1991) Cypermethrin (No. 82, 1989) Kelevan (No. 66, 1986) Cypermethrin, alpha- (No. 142, 1992) Lasers and optical radiation (No 23, 1982) DDT and Its derivatives (No. 9, 1979) Lead (No. 3, 1977)' DDT and its derivatives - environmental aspects Lead - environmental aspects (No. 85, 1989) (No. 83, 1989) Lindane (No. 124, 1991) Deltamethrin (No. 97, 1990) Magnetic fields (No. 69, 1987) Diaminotoluenes (No. 74, 1987) Man-made mineral fibres (No. 77, 1988)

• Out of print continued inside back cover This report contains the collective views of an in­ ternational group of experts and does not necessarily represent the decisions or the stated policy of the United Nations Environment Programme, the Interna­ tional Labour Organisation, or the World Health Organization.

Environmental Health Criteria 162

BROMINATED DIPHENYL ETHERS

First draft prepared by Dr G.J. van Esch, B1lthoven, Netherlands

Published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization

World Health Organization Geneva, 1994 The International Programme on Chemical Safety (IPCS) is a joint venture of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization. The main obJective of the IPCS is to carry out and disseminate evaluations of the effects of chermcals on human health and the quality of the envuonment. Supporting activities include the development of epidermolog1cal, expenmentallaboratory, and risk-assessment methods that could produce internationally comparable results, and the development of manpower in the field of toxicology. Other activ1ties carried out by the IPCS include the development of know-how for copmg with chemical accidents, coordination of laboratory testing and epidemiological studies, and promotion of research on the mechanisms of the biological action of chemicals.

WHO Library Cataloguing in Publication Data

Brominated diphenylethers.

(Environmental health critena ; 162)

l.Phenyl ethers - adverse effects 2.Environmental exposure 3. Occupational exposure l.Senes

ISBN 92 4 157162 4 (NLM Classification: QD 34l.E7) ISSN 0250-863X

The World Health Orgamzatwn welcomes requests for perrmsswn to reproduce or translate its publications, in part or in full. Applications and enquiries should be addressed to the Office of Pubhcatwns, World Health Organization, Geneva, Switzerland, wh1ch will be glad to prov1de the latest information on any changes made to the text, plans for new editions, and reprints and translatiOns already ava1lable.

©World Health Organization 1994

Publications of the World Health Organization enJOY copynght protection in accordance w1th the proviswns of Protocol 2 of the Universal Copyright Convention. All rights reserved. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretanat of the World Health Organization concerning the legal status of any country, terntory, c1ty or area or of 1ts authonties, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or of certain manufacturers' products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a smlilar nature that are not mentioned. Errors and ormssions excepted, the names of propnetary products are distinguished by initial capital letters.

PRINTED IN FINLAND 94/10266- V AM MALA - 5500 CONTENTS

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GLOSSARY 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18 BROMINATED DIPHENYL ETHERS - GENERAL

INTRODUCTION 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 25 1. GENERAL REMARKS 27

20 GENERAL INFORMATION ON BROMINATED DIPHENYL ETHERS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 31 2 ol Analytical methods 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 31 202 Production levels and processes 0 0 0 0 0 0 0 0 0 0 0 31 203 Resins, polymers and substrates in which PBDE are used 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 34 30 FORMATION OF BROMINATED DIBENZOFURANS AND DIBENZODIOXINS FROM POL YBROMINATED DIPHENYL ETHERS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 39 3 ol General 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 39 302 Additional data on pyrolysis of non-specified PBDE and/or polymers containing non-specified PBDE 0 0 0 0 0 0 0 0 0 0 0 0 41 40 WORKPLACE EXPOSURE STUDIES 0 0 0 0 0 0 0 0 0 0 44 401 Exposure to PBDE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 44 402 Exposure to PBDF/PBDD 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 44 50 EXPOSURE OF THE GENERAL POPULATION 0 0 0 46 5 ol General population 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 46 502 Possible exposure to PBDE and PBDF/PBDD 0 0 0 46 50201 Television sets 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 46 50202 Fire tests and fire accidents 0 0 0 0 0 0 0 0 0 0 47 60 ENVIRONMENTAL POLLUTION BY PBDE 0 0 0 0 0 51

601 Ultimate fate following use 0 0 0 0 0 0 0 0 0 0 0 0 0 0 51 602 Air 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 52

3 EHC 162: Brominated diphfHJylethers

6.3 Soil ...... 52 6.4 Water 52 6.5 Sediments and sewage sludge ...... 53 6.6 Aquatic vertebrates ...... 53 6.7 Aquatic mammals ...... 54 6.8 Terrestrial vertebrates ...... 54 6.8.1 Birds ...... 55 6.8.2 Humans 55

DECABROMODIPHENYL ETHER ...... 57

1. SUMMARY, EVALUATION, CONCLUSIONS, AND RECOMMENDATIONS ...... 59 1.1 Summary and evaluation ...... 59 1.1.1 Identity, physical and chemical properties ...... 59 1.1.2 Production and uses ...... 59 1.1.3 Environmental transport, distribution, and transformation ...... 59 1.1.4 Environmental levels and human exposure . 60 1.1.5 Kinetics and metabolism in laboratory animals and humans ...... 61 1.1.6 Effects on laboratory mammals and in vitro test systems ...... 62 1.1. 7 Effects on humans ...... 63 1.1. 8 Effects on other organisms in the laboratory and field ...... 63 1.2 Conclusions ...... 63 1.2.1 DeBDE ...... 63 1.2.2 Breakdown products ...... 64 1. 3 Recommendations ...... 64 1.3.1 General ...... 64 1.3.2 Further studies ...... 65 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS ...... 66 2.1 Identity ...... 66 2.1.1 Pure substance ...... 66 2.1.2 Technical product ...... 67 2.2 Physical and chemical properties ...... 68

4 2.3 Analytical methods ...... 70 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE ...... 71 3 .1 Natural occurrence ...... 71 3.2 Anthropogenic sources ...... 71 3.2.1 Production levels and processes ...... 71 3.2.2 Uses ...... 72 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION ...... 73 4.1 Transport and distribution between media . . . . . 73 4.1.1 Extraction from polymers ...... 73 4.2 Biotransformation ...... 73 4.3 Abiotic degradation ...... 73 4.3.1 Photodegradation ...... 73 4.3.2 Pyrolysis ...... 75 4.3.3 Combustion of DeBOE and polymers containing DeBOE ...... 76 4.3.3.1 Pyrolysis studies ...... 76 4.3.3.2 Workplace exposure studies . . . . 93 4.4 Ultimate fate following use ...... 10I 4.4.I General ...... 101 4.4.2 Exposure of the general population 102 4.5 Fire accident ...... 102 4.6 Simulated fire conditions ...... 103 4.7 Bioaccumulation ...... I04 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE ...... 105 5 .I Environmental levels ...... I 05 5.1.1 Air ...... 105 5.1.2 Water ...... 105 5.1.3 Aquatic sediments ...... 105 5 .1. 4 Aquatic and terrestrial organisms ...... 106 5.2 Exposure of humans ...... 107 5.2.1 Occurrence of DeBOE in human tissues 107 5.2.2 Occupational exposure ...... 107

5 EHC 162: BrominattHJ diphenyl ethers

60 KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 109 601 Absorption and elimination 0 0 0 0 0 0 0 0 0 0 0 0 0 0 109 602 Distribution 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 110 603 Retention and turnover 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 111 70 EFFECTS ON LABORATORY MAMMALS AND IN Vl1RO TEST SYSTEMS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 112 7 01 Single exposure 0 0 0 0 0 . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 112 7 0101 Oral: Rat 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 112 701.2 Dermal: Rabbit 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 112

701.31nhalation:Rat oooooooooooooooooo 112 702 Short-term exposure 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . 0 0 0 113 70201 Oral 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 113 70201.1 Mouse 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 113 7 0201.2 Rat 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 113 70202 Inhalation 0 0 0 0 0 . 0 . 0 0 0 0 0 0 0 0 0 0 0 0 0 115 702.201 Rat 0 . 0 0 0 0 0 0 0 0 0 0 0 0 .. 0 0 0 115 7 03 Long-term exposure 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . 0 0 115 7 0301 Oral 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 115 70301.1 Mouse 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 115 70301.2 Rat 0 0 0 . 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 116 7.4 Skin and eye irritation; sensitization 0 0 0 0 0 0 0 0 0 116 7.401 Skin irritation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 116 7.402 Eye irritation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 116 7.4 03 Sensitization 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 117 7.404 Chloracnegenic activity 0 0 0 0 0 0 0 0 0 0 0 0 0 117 7 05 Reproductive toxicity, embryotoxicity, and teratogenicity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 117 7 05 01 Reproductive toxicity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 117 7 05 02 Teratogenicity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 118 7 06 Mutagenicity and related end-points 0 0 0 0 0 0 0 0 0 119 70601 Mutation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 119 70602 Chromosomal effects 0 0 0 0 0 0 0 0 0 0 0 0 0 0 119 7 07 Carcinogenicity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 120 7 07 01 Oral 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . 0 120 7070101 Mouse 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 120 7 07 01.2 Rat 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 120 708 Other special studies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . 0 122 70801 Liver 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 122

6 7.8.2 Miscellaneous ...... 122 7.8.3 Toxicity of soot, char, and other waste products from combustion of DeBDE-containing polymers ...... 123 7.8.3.1 Acuteoraltoxicity ...... 123 7.8.3.2 Skin irritation and comedogenicity 123 7.8.3.3 Eye irritation ...... 125 8. EFFECTS ON HUMANS ...... 126 8.1 General population exposure ...... 126 8.2 Occupational exposure ...... 126 8.2.1 Skin sensitization ...... 126 8.2.2 Neurotoxicity ...... 126 8.2.3 Epidemiological studies ...... 127 9. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD ...... 129 10. PREVIOUS EVALUATIONS BY INTERNATIONAL BODIES ...... 130

NONABROMODIPHENYL ETHER 131

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS ...... 133 1.1 Summary and evaluation ...... 133 1.2 Recommendations ...... 133 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS 134 2.1 Identity ...... 134 2.2 Physical and chemical properties ...... 135 2.3 Analytical methods ...... 135 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE ...... 136 3.1 Natural occurrence ...... 136 3.2 Anthropogenic sources ...... 136 3.2.1 Production levels and processes ...... 136 3.2.2 Uses ...... 136

7 EHC 162: Brominated dipheny/ ethers

OCTABROMODIPHENYL ETHER 137

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 139 1.1 Summary and evaluation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 139 1.1.1 Identity, physical and chemical properties 139 1.1.2 Production and uses 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 139 1.1.3 Environmental transport, distribution, and transformation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 139 1.1.4 Environmental levels and human exposure 140 10105 Kinetics and metabolism in laboratory animals and humans 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 140 10106 Effects on laboratory mammals and in vitro test systems 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 141 1.1. 7 Effects on humans 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 142 1010 8 Effects on other organisms in the laboratory and field 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 142 1.2 Conclusions 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 142 1.201 OBDE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 142 1.202 Breakdown products 0 0 0 0 0 0 0 0 0 0 • 0 0 0 143 1.3 Recommendations 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 143 1.301 General 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 143 1.302 Further studies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 144 20 IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS 145 201 Identity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 145 201.1 Technical product 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 146 203 Physical and chemical properties 0 0 0 0 0 0 0 0 0 0 0 146 203 Analytical methods 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 147 30 SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 148 3 01 Natural occurrence 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 148 302 Anthropogenic sources 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 148 30201 Production levels and processes 0 0 0 0 0 0 0 148 30202 Uses 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ... 0 0 0 . . 148

8 40 ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 149 401 Biotransformtion 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 149 4o2 Abiotic degradation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 149 4o2o1 Pyrolysis of octabromodiphenyl ether 0 0 0 0 149 40202 Pyrolysis studies with polymers containing octabromodiphenyl ether 0 0 0 0 0 0 0 0 0 0 0 0 149 40203 Behaviour of octabromodiphenyl ether during processing 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 150 403 Bioaccumulation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 151 4.4 Ultimate fate following use 0 0 0 0 0 0 0 0 0 0 0 0 0 0 151 50 ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 152 501 Environmental levels 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 152 501.1 Water 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 152 501.2 Aquatic sediments 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 152 501.3 Aquatic and terrestrial organisms 0 0 0 0 0 0 152 502 Exposure of the general population 0 0 0 0 0 0 0 0 0 152 503 Occupational exposure during manufacture, formulation or use 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 153 60 EFFECTS ON LABORATORY MAMMALS AND IN VIIRO TEST SYSTEMS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 154 601 Single exposure 154 601.1 Oral: Rat 154 601.2 Dermal: Rabbit 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 154 601.3 Inhalation: Rat 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 154 602 Short-term exposure 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 155 60201 Oral: Rat 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 155 60202 Inhalation: Rat 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 157 603 Long-term exposure 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 158 6.4 Skin and eye irritation; sensitization 0 0 0 0 0 0 0 0 0 158 6.401 Skin irritation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 158 6.402 Eye irritation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 159 605 Teratogenicity, reproductive toxicity, and embryotoxicity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 159 605 01 Teratogenicity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 159 60501.1 Oral: Rat 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 159 60501.2 Oral: Rabbit 0 0 0 0 0 0 0 0 0 0 0 0 0 0 160

9 EHC 162: Brominated diphenylethers

6.6 Mutagenicity and related end-points ...... 161 6.6.1 DNA damage ...... 161 6.6.2 Mutation ...... 161 6.6.3 Chromosomal effects ...... 161 6.7 Carcinogenicity ...... 161 6.8 Other special studies ...... 162 6.8.1 Liver ...... 162 6.9 Appraisal ...... 163

HEPT ABROMODIPHENYL ETHER 165

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS ...... 167 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, AND ANALYTICAL METHODS . . . 168 2.1 Identity ...... 168 2.2 Physical and chemical properties ...... 168 2.3 Analytical methods ...... 169 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE ...... 170 3.1 Natural occurrence ...... 170 3. 2 Anthropogenic sources ...... 170 3.2.1 Production levels and proc,~sses ...... 170 4. ENVIRONMENTAL TRANSPORT, JDISTRIBUTION, AND TRANSFORMATION ...... 171 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE ...... 172 6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS ...... 173 6.1 Single exposure ...... 173 6.2 Skin and eye irritation; sensitization ...... 173

HEXABROMODIPHENYL ETHER ...... 175

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS ...... 177

10 20 IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS 0 0 0 0 0 0 178 201 Identity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 178 201.1 Technical product 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 178 202 Physical and chemical properties 0 0 0 0 0 0 0 0 0 0 0 179 203 Analytical methods 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 179 30 SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 180 3 01 Natural occurrence 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 180 302 Anthropogenic sources 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 180 3o3 Uses 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 180 40 ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 181 50 ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 182 501 Levels in the environment 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 182 5 01 01 Water 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 182 501.2 Aquatic sediments 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 182 501.3 Aquatic and terrestrial organisms 0 0 0 0 0 0 182 502 General population exposure 0 0 0 0 0 0 0 0 0 0 0 0 0 183 60 KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 184

PENTABROMODIPHENYL ETHER 0 0 0 0 0 0 0 0 0 0 0 0 0 185

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 187 1.1 Summary and evaluation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 187 1.1.1 Identity, physical and chemical properties 0 187 1.1.2 Production and uses 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 187 10103 Environmental transport, distribution and transformation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 187 1.1.4 Environmental levels and human exposure 0 188 1.1.5 Kinetics and metabolism in laboratory animals and humans 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 189 10106 Effects on laboratory mammals and in vitro test systems 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 189

11 EHC 162: Brominated diphenylethsrs

1010 7 Effects on humans 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 189 1010 8 Effects on other organisms in the laboratory and field 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 190

1.2 Conclusions 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 190

1.201 PeBDE 0 0 0 0 0 0 0 0 o o o o 0 0 0 0 0 0 0 0 o o o 190 1.202 Breakdown products 0 0 0 0 0 0 0 0 0 0 0 0 0 0 190 1.3 Recommendations 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 191 1.301 General 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 191

1.302 Further studies 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 191 20 IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS 193 201 Identity 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 193 201.1 Technical product 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 194 202 Physical and chemical properties 0 0 0 0 0 0 0 0 0 0 0 195 203 Analytical methods 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 195 30 SOURCES OF HUMAN AND ENVIRONMENTAL

EXPOSURE 0 0 0 0 0 0 0 0 0 0 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 o 197 3 01 Natural occurrence 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 197 302 Anthropogenic sources 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 197 30201 Production levels and processes 0 0 0 0 0 0 0 197 30202 Uses 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 197 40 ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 198 401 Pyrolysis 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 198 402 Workplace exposure studies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 198 403 Bioaccumulation 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 198 4.4 Ultimate fate following use 0 0 0 0 0 0 0 0 0 0 0 0 0 0 199 50 ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200 5 01 Levels in the environment 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200 5 01.1 Sediment and sewage sludge 0 0 0 0 0 0 0 0 0 200 501.2 Fish and shellfish 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 201 501.3 Aquatic mammals 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 202 501.4 Terrestrial mammals 0 0 0 0 0 0 0 0 0 0 0 0 0 0 202 501.5 Birds 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 202 502 General population 203

12 6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS ...... 205 7. EFFECTS ON LABORATORY MAMMALS AND IN V/1RO TEST SYSTEMS ...... 206 7.1 Single exposures ...... 206 7. 1. 1 Oral ...... 206 7 .1.2 Dermal ...... 206 7. 1. 3 Inhalation ...... 207 7.2 Short-term exposure ...... 207 7.3 Long-term exposure ...... 209 7.4 Skin and eye irritation; sensitization ...... 209 7 .4.1 Skin irritation ...... 209 7 .4.2 Eye irritation ...... 209 7.5 Reproductive toxicity, embryotoxicity and teratogenicity ...... 209 7.6 Mutagenicity and related end-points ...... 210 7.7 Carcinogenicity ...... 210 7.8 Other special studies ...... 210

TETRABROMODIPHENYL ETHER ...... 213

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS ...... 215 1.1 Summary and evaluation ...... 215 1.1.1 Identity, physical and chemical properties 215 1.1.2 Production and uses ...... 215 1.1.3 Environmental transport, distribution, and transformation ...... 215 1.1. 4 Environmental levels and human exposure . 216 1.1.5 Effects on laboratory mammals and

in vitro test systems . . c • • • • • • • • • • • • 217 1.1.6 Kinetics and metabolism in laboratory animals and humans ...... 217 1.1.7 Effects on humans ...... 217 1.1.8 Effects on other organisms in the laboratory and field ...... 217 1.2 Conclusions ...... 218 1.2.1 TeBDE ...... 218 1.2.2 Breakdown products ...... 218 1.3 Recommendations ...... 219

13 EHC 162: Brominated diphenyl ethers

1.3.1 General ...... 219 1.3.2 Further studies ...... 219 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS 221 2.1 Identity ...... 221 2.2 Physical and chemical properties ...... 221 2.3 Analytical methods ...... 222 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE ...... 223 3.1 Natural occurrence ...... 223 3.2 Anthropogenic sources ...... 223 3.2.1 Production levels and processes ...... 223 3.2.2 Uses ...... 223 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION ...... 224 4.1 Pyrolysis ...... 224 4.2 Ultimate fate following use ...... 224 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE ...... 225 5.1 Environmental levels ...... 225 5 .1.1 Soil and sediment ...... 225 5.1.2 Fish and shellfish ...... 226 5.1.3 Birds ...... 227 5.1.4 Aquatic mammals ...... 228 5.1.5 Terrestrial mammals ...... 229 5.2 General population exposure ...... 229 6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS 230

TRIBROMODIPHENYL ETHER 231

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS ...... 233 1.1 Summary and evaluation ...... 233 1.2 Recommendations ...... 233

14 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS ...... 234 2.1 Identity ...... 234 2.2 Physical and chemical properties ...... 234 2.3 Analytical methods ...... 235 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE ...... 236 4. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE ...... 237 4.1 Environmental levels ...... 237 4.1.1 Birds ...... 237

DIBROMODIPHENYL ETHER ...... 239

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS ...... 241 1.1 Summary and evaluation ...... 241 1. 2 Recommendations ...... 241 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS ...... 242 2.1 Identity ...... 242 2.2 Physical and chemical properties ...... 242 2.3 Analytical methods ...... 243 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE ...... 244 3.1 Natural occurrence ...... 244 3.2 Anthropogenic sources ...... 244 3.2.1 Production levels and processes ...... 244 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION ...... 245 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE ...... 246 5.1 Environmental levels ...... 246 5.1.1 Water ...... 246 5.1.2 Soil/sediment ...... 246

15 EHC 162: BrominatfKI diphenylethtH's

5.1.3 Birds ...... 246 5.2 General population exposure 246 6. EFFECTS ON LABORATORY MAMMALS AND IN VI1RO TEST SYSTEMS ...... 247 6.1 Single exposure ...... 247 6.2 Other special studies ...... 247 6.2.1 Liver ...... 247

MONOBROMODIPHENYL ETHER ...... 249

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS ...... 251 1.1 Summary and evaluation ...... 251 1.1.1 Physical and chemical properties ...... 251 1.1.2 Production and uses ...... 251 1.1.3 Environmental transport, distribution, and transformation ...... 251 1.1.4 Environmental levels and human exposure . 252 1.1.5 Kinetics and metabolism in laboratory animals :md humans ...... 252 1.1.6 Effects on laboratory mammals and in vitro test systems ...... 252 1.1. 7 Effects on humans ...... 252 1.1. 8 Effects on other organisms in the laboratory and field ...... 252 1.2 Conclusions and recommendations ...... 252 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS ...... 254 2.1 Identity ...... 254 2.2 Physical and chemical properties ...... 255 2.3 Analytical methods ...... 255 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE ...... 256 3.1 Natural occurrence ...... 256 3.2 Anthropogenic sources ...... 256 3.2.1 Production levels and processes ...... 256 3.2.2 Uses ...... 256

16 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION ...... 257 4.1 Transport and distribution between media . . . . . 257 4.2 Biotransformation ...... 257 4.2.1 Biodegradation ...... 257

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE ...... 259 5.1 Environmental levels ...... 259 5 .1. 1 Water ...... 259 5 .1.2 Soil/Sediment ...... 259 5 .1. 3 Aquatic organisms ...... 260 6. EFFECTS ON LABORATORY MAMMALS AND IN VIIRO TEST SYSTEMS ...... 261 6.1 Reproductive toxicity, embryotoxicity, teratogenicity ...... 261 6.2 Carcinogenicity 261 7. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD ...... 263 REFERENCES ...... 265 RESUME ET EVALUATION, CONCLUSIONS ET RECOMMANDA TIONS ...... 283 RESUMEN, EVALUACION, CONCLUSIONES Y RECOMENDACIONES ...... 317

17 GLOSSARY

PBDE polybrominated diphenyl ethers MBDE monobromodiphenyl ethers DiBDE dibromodiphenyl ethers TrBDE tribromodiphenyl ethers TeBDE tetrabromodiphenyl ethers PeBDE pentabromodiphenyl ethers HxBDE hexabromodiphenyl ethers HpBDE heptabromodiphenyl ethers OBDE octabromodiphenyl ethers NBDE nonabromodiphenyl ethers DeBDE decabromodiphenyl ethers

PBDF polybrominated dibenzofurans TeBDF tetrabromodibenzofurans PeBDF pentabromodibenzofurans HxBDF hexabromodibenzofurans HpBDF heptabromodibenzofurans

PBDD polybrominated dibenzodioxins TeBDD tetrabromodibenzodioxins PeBDD pentabromodibenzodioxins HxBDD hexabromodibenzodioxins HpBDD heptabromodibenzodioxins

PBBz polybrominated benzenes PBP polybrominated phenols PBN pol ybrominated naphthalenes PBB polybrominated biphenyls PCB polychlorinated biphenyls THP Tetrakis(hydroxymethyl)phosphonium salts

ABS acrylonitrile-butadiene-styrene BASF Badische Anilin und Soda Fabrik BFRIP Brominated Flame Retardant Industry Panel BOD biochemical oxygen demand

18 CEFIC Conseil Europeen de l'Industrie Chimique (European Chemical Industry Council) DTA differential thermal analysis EBFRIP European Brominated Flame Retardant Industry Panel EEC European Economic Community ER epoxy resin FY Fiscal Year GC/ECD gas chromatography/electron capture detector GC/MS gas chromatography/mass spectrometry HIPS high impact polystyrene HPLC high pressure liquid chromatography HRGC/MS high resolution gas chromatography/mass spectrometry IG ignition loss NCI negative chemical ionization NHATS National Human Adipose Tissue Survey NIOSH National Institute of Occupational Safety and Health PA polyamide PAN polyacrylonitrile PBT polybutylene terephthalate PE polyethylene PET polyethylene terephthalate pp polypropylene PR phenolic resin PS polystyrene PUR polyurethane PVC polyvinylchloride SIM selective ion monitoring TGA thermal gravimetric analysis UPE unsaturated (Thermoset) polyesters US EPA United States Environmental Protection Agency US NTP United States National Toxicology Program XPE cross-linked polyethylene

19 WHO TASK GROUP ON ENVIRONMENTAL HEALTH CRITERIA FOR BROMINATED DIPHENYL ETHERS

Members

Dr L.A. Albert, Consultores Ambientales Asociados, S.C., Xalapa, Veracruz, Mexico (Vice-Chairman)

DrS. Dobson, Institute of Terrestrial Ecology, Monks Wood Experimental Station, Cambridgeshire, United Kingdom

Professor B. Jansson, Institute of Applied Environmental Research, Stockholm University, Solna, Sweden

Dr J. Kielhorn, Fraunhofer Institute for Toxicology and Aerosol Research, Hanover, Germany

Dr M. Luotamo, Finnish Institute of Occupational Health, Helsinki, Finland

Professor Wai-On Phoon, Worksafe Australia, and University of Sydney, Sydney, Australia (Chairman)

Mr J. Rea, Department of Environment, London, United Kingdom

DrS. Sleight, Department of Pathology, Michigan State University, East Lansing, USA

Observers

Dr M.L. Hardy, Health and Environment, Ethyl Corporation, Baton Rouge, USA

Dr D.L. McAllister, Quality Assurance and Research Services, Great Lakes Chemical Corporation, West Lafayette, Indiana, USA

20 Secretariat

Dr K.W. Jager, International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland (Secretary)

Dr G.J. van Esch, Bilthoven, The Netherlands (Rapporteur)

21 NOTE TO READERS OF THE CRITERIA DOCUMENTS

Every effort has been made to present information in the criteria documents as accurately as possible without unduly delaying their publication. In the interest of all users of the environmental health criteria documents, readers are kindly requested to communicate any errors that may have occurred to the Director of the International Programme on Chemical Safety, World Health Organization, Geneva, Switzerland, in order that they may be included in corrigenda, which will appear in subsequent volumes.

* * *

A detailed data profile and a legal file can be obtained from the International Register of Potentially Toxic Chemicals, Case Postale 356, 1219 Chatelaine, Geneva, Switzerland (Telephone No. 9799111).

* * *

This publication was made possible by grant number 5 U01 ES02617-14 from the National Institute of Environmental Health Sciences, National Institutes of Health, USA.

NOTE: The proprietary information contained in this document cannot replace documentation for registration purposes, because the latter has to be closely linked to the source, the manufacturing route, and the purity/impurities of the substance to be registered. The data should be used in accordance with paragraphs 82-84 and recommendations paragraph 90 of the Second F AO Government Consultation (1982).

22 ENVIRONMENTAL HEALTH CRITERIA FOR BROMINATED DIPHENYL ETHERS

A WHO Task Group on Environmental Health Criteria for Brominated Diphenyl Ethers met at the World Health Organization, Geneva, from 28 June to 2 July 1993. Dr K.W. Jager, of the IPCS, welcomed the participants on behalf of Dr M. Mercier, Director IPCS, and the three cooperating organizations (UNEP/ILO/WHO). The Group reviewed and revised the draft criteria monograph and made an evaluation of the risks for human health and the environment from exposure to brominated diphenyl ethers. The first draft of the monograph was prepared by Dr G .J. van Esch of the Netherlands, who also prepared the second draft, incorporating comments received following circulation of the first draft to the IPCS contact points for Environmental Health Criteria monographs. Dr K.W. Jager of the IPCS Central Unit was responsible for the scientific content of the monograph, and Mrs M.O. Head of Oxford, England, for the editing. The fact that industry made proprietary toxicological information available to the IPCS and the Task Group on the products under discussion is gratefully acknowledged. This allowed the Task Group to make its evaluation on a more complete data base. The efforts of all who helped in the preparation and finalization of the document are gratefully acknowledged.

23

BROMINATED DIPHENYL ETHERS

GENERAL INTRODUCTION

1. GENERAL REMARKS

This Environmental Health Criteria monograph on brominated diphenyl ethers has been prepared as part of an overview on the impact of a number of flame retardants on human health and the environment. The group of polybrominated diphenyl ethers (PBDE) has been selected as a priority because of the recent interest in these substances. Only products based on penta-, octa-, and decabromodiphenyl ethers are of commercial interest. The general chemical formula of brominated diphenyl ethers is:

6 0 6'

Polybrominated diphenyl ethers (PBDE) have a large number of congeners, depending on the number and position of the bromine atoms on the two phenyl rings. The total number of possible congeners is 209, and the numbers of isomers for mono-, di-, tri- up to decabromodiphenyl ethers are: 3, 12, 24, 42, 46, 42, 24, 12, 3, and I, respectively. The commercial PBDE are produced hy the bromination of diphenyl oxide under certain conditions, which result in products containing mixtures of brominated diphenyl ethers (see the individual PBDE). The compositions of commercial DeBDE. OBDE, and PeBDE are given in Table 1.

27 1\) Q:)

Table 1. Compos1t1on of commercial brominated diphenyl ethers

Product Compos1t10n

PBDE8 TrBDE TeBDE PeBDE HxBDE HpBDE OBDE NBDE DeBDE

DeBDE 0.3-3% 97-98%

OBDE 10-12% 43-44% 31-35% 9-11% 0-1%

PeBDE 0-1% 24-38% 50-62% 4-8%

TeBDEb 7.6% 41-41.7% 44.4-45% 6-7%

8 Unknown structure. bNo longer commercially produced. Analysis of one smgle sample. General introduction

No, or virtually no, data are available on dibromo-, tri­ bromo-, hexabromo-, heptabromo-, and nonabromodiphenyl ether (DiBDE, TrBDE, HxBDE, HpBDE, and NBDE, respectively). Flame retardants containing predominantly penta-, octa- and decabromodiphenyl ethers are commercially produced (with tetrabromodiphenyl ether as a major component of "pentabromo­ diphenyl ether", which is a mixture). The commercial PBDE are rather stable compounds with boiling points ranging between 310 and 425 oc and with low vapour pressures, e.g., 3.85 up to 13.3 Pa at 20-25 oc; they are lipophilic substances. Their solubility in water is very poor, especially that of the higher brominated diphenyl ethers, and the n-octanol!water partition coefficients (log Pow) range between 4.28 and 9.9. Polybrominated diphenyl ethers have not been reported to occur naturally in the environment, but other types of brominated diphenyl ethers have been found in marine organisms (Carte & Faulkner, 1981; Faulkner, 1990). The presence in the environment of some of the brominated diphenyl ethers has been documented, the highest concentration being 1 g/kg sediment in streams or ponds in the vicinity of a manufacturing facility. Data on environmental fate, although limited to MBDE, DiBDE, and DeBDE, suggest that biodegradation is not an important degradation pathway for the PBDE, but that photodegradation may play a significant role. Many reports have appeared in the literature describing the behaviour of brominated flame retardants under pyrolytic conditions. In general, these reports have indicated that maximum concentrations of PBDF and/or PBDD Wt""e observed at tempera­ tures of 400-800 oc and that the 2,3, 7 ,8-substituted compounds were seen only in very low concentrations. Processing of the polymers under abusive or extreme conditions produced higher levels of PBDF, but the concentrations were significantly lower than the values previously reported from laboratory pyrolysis studies. 2,3, 7 ,8-Brominated isomers were only found at low levels in a sample abusively processed. The 2,3, 7 ,8-brominated isomers, which are of concern for toxicological

29 EHC 162: Brominated diphenylethers

and regulatory reasons, were not detected under normal processing conditions. The results of the laboratory pyrolysis experiments with PBDE, showed that PBDF and/or PBDD were formed in various concentrations, depending on the type of PBDE, the polymer matrix, the specific processing conditions (temperature, presence of oxygen, etc.) and equipment used, and the presence of Sb20 3. Behaviour of PBDE is strongly dependent upon the polymer matrix and upon the specific processing conditions mentioned above, thus laboratory pyrolysis experiments can hardly be used as reliable models to predict behaviour in commercial moulding operations.

30 2. GENERAL INFORMATION ON BROMINATED DIPHENYL ETHERS

2.1 Analytical methods

Several methods to determine residues of PBDE in various media (air, sewage sludge, sediment, human adipose tissue, marine organisms, fish, and feed) as well as in commercial products have been reported. For details, see Table 2. In general, sample extraction and clean-up techniques for the analysis of PBDE residues in biological samples are similar to those developed for PBB (see EHC 152: Polybrominated biphenyls), though the chromatographic conditions have to be modified in view of the long retention times of the highly brominated PBDE. Temperature programming and the use of capillary columns have been found to be very useful for the separation of the different congeners of PBDE. Recovery for the different PBDE is generally higher than 80%. Most methods are based on extraction with organic solvents, such as hexane/ acetone, hexane/diphenyl ether, acetone, etc, purification of the extracts by gel permeation or adsorption chromatography, and determination mainly by gas chromatography, either with electron capture detection (ECD), or, coupled with mass spectrometry (MS). A multi-residue method has also been developed that includes a multi-step separation enabling the determination of several polychlorinated and polybrominated pollutants in biological samples (Jansson et al., 1991).

2.2 Production levels and processes

According to the information given by the European Brominated Flame Retardant Industry Panel (EBFRIP), eight manufacturers are currently producing polybrominated diphenyl ethers. They are: Dead Sea Bromines/Eurobrome (The Netherlands); Atochem (France); Ethyl Corporation (USA); Great Lakes Chemical Corporation (USA); Tosoh (Japan); Matsunaga (Japan); Nippo (Japan); Great Lakes Chemical Ltd (United Kingdom).

31 (.<) 1\l

Table 2. Analytical methods for PBDE

Sample Extraction and clean-up Separation and Limit of Reference detection determination

Sewage extract w1th chloroform; evaporate and dissolve GC/MS 0.06 mg/kg Kaart & Kokk residue in ethanol (1987)

Sed1ment extract with acetone; clean-up on Flons1l NAA; < 5 pg/kg Watanabe et el. GC/EC < 5 pg/kg (1987b)

Fish extract w1th acetone-hexane + hexane-ethyl ether; GC/EC; lim1t of Andersson & treatment With sulfunc ac1d or clean-up on alumina; GC/MS detection Blomkvist chromatography on s11ica gel 0. 1 mg/kg fat (1981)

Animal tissues homogenize; extract With n-hexane-acetone; GC/MS (NCI) 10 ng/kg Jansson et el. (Mult1-res1due treatment w1th sulfuric acid; gel permeation (1991) method) chromatography; chromatography or silica gel; chromatography or activated charcoal

Rat liver extract with tetrahydrofuran HPLC Rogers & Hill (1980) Table 2 (continued)

F1sh extract freeze-dned powdered sample w1th pet. ether; GC/MS < 5 pg/kg fat Kruger ( 1988) gel permeation chromatography; clean-up on Flonsil; (NCI/SIM) elute With hexane

Cow's m1lk centrifuge; gel permeation chromatography; clean-up GC/MS < 2.5 pg/kg fat Kruger (1988) on Flons1l; elute with hexane (NCI/SIM)

Human m1lk extract with potass1um oxalate/ethanol/d1ethyl GC/MS < 0.6 !Jg/kg fat Kruger (1988) ether/pentane; gel permeation chromatography; clean­ (NCI/SIM) up on Florisil; elute with hexane

Human adipose extract with methylene chlonde; evaporate; clean-up HRGC/HRMS8 lim1t of Cramer et al. tissue on silica gel followed by clean-up on alumina and on a detection (1990a,b) carbon/silica gel column 0.73-120 ng!kg (different congeners)

Commercial PBDE homogenize and d1ssolve in tetrachloromethane for HPLC; GC/MS; deKok et al. HPLC and GC/MS or n-hexane for TLC/UV TLC/UV (1979)

8 H1gh resolution gas chromatography/high resolution mass spectrometry.

w w EHC 162: Brominated diphenylethers

The annual global consumption of PBDE is 40 000 tonnes (30 000 tonnes of DeBDE; 6000 tonnes OBDE and 4000 tonnes PeBDE) (Arias, 1992). It has been reported that the use of brominated flame retardants in Japan increased from 2500 tonnes in 1975 to 22 100 tonnes in 1987 (Watanabe & Tatsukawa, 1990). The production and import figures for the European Economic Community (EEC) are given in Table 3.

Table 3. Production and import quantities of PBDE 1n metric tonnes in the EEC ..

1986 1987 1988 1989

Production 4276 3624 4066 3843

Import 4310 3492 4955 7103

Total 8586 7116 9021 10 946

.. From: EBFRIP (19901.

Data on the usage of PBDE are available for some individual European countries. Germany uses 3000-5000 tonnes/year, Sweden 1400-2000 tonnes/year, and The Netherlands 3300-3700 tonnes/year (OECD, 1991; van Zorge, 1992), but Pijnenburg & Everts (1991) and Pijnenburg et al. (1992) reported a level of 2500 tonnes PBDE for the last country. In the United Kingdom, up to 2000 tonnes per year are used (UK DOE, 1993). Because of the significant reduction in the fire hazard for the public achieved by the use of PBDE in a wide range of applications, particularly in the furniture industry, and electrical/computer components and housing, the consumption of PBDE has significantly increased over the last years (EBFRIP, 1990).

2.3 Resins, polymers, and substrates in which PBDE are used

The major uses of the polybrominated diphenyl ethers in descending order of importance are: high-impact polystyrene, ABS, flexible polyurethane foam, textile coatings (not clothing),

34 General introduction

wire and cable insulation, electrical/electronic connectors and other interior parts. These applications account for at least 80-90% of the consumption of brominated diphenyl ethers in the USA. Brominated diphenyl ethers are used as additive flame retardants. Additive flame retardants are incorporated into the plastic matrix like other additives, such as plasticizers. The ideal additive is inexpensive, colourless, easily blended, compatible, heat and light stable, efficient, permanent, and has no deleterious effect on the properties of the base polymer. The most important limitations are incompatibilities that affect the physical properties of the polymers and the tendency for additives to be fugitive. These additive flame retardants are much more prone to leaching or escape from the finished polymer product than the reactive flame retardants (Hutzinger et al., 1976; Hutzinger & Thoma, 1987; Larsen, 1980). The uses of penta-, octa-, and decabromodiphenyl ethers in the different resins, polymers, and substrates are shown in Table 4. The principal applications of these PBDE-containing substances are shown in Table 5. PBDE are used in the different resins, polymers, and substrates at levels ranging from 5 up to 30%. The quantities used for each application are not publicly available. In consumer products, resins containing PBDE are typically used in interior parts, minimizing the potential for exposure of the public. The incorporation of the PBDE into the polymer matrix further reduces the possibilities of exposure (EBFRIP, 1990).

35 EHC 162: Brominated diphenyl ethers

Table 4. Use of penta- (PeBDE), octa- (OBOE), and decabromodiphenyl ethers (DeBOE) in resms, polymers, and substrates8

Resins/polymers/substrates DeBOE OBOE PeBDE

ABS X

Epoxy-resins X

Phenolic resins X X

PAN X

PA X X

PBT X X

PE/XPE X

PET X

pp X

PS, HIPS X X

PVC X X

PUR X

UPE X X

Rubber X X

Paints/lacquers X X

Textoles X X

8 From: EBFRIP (1990); UK Department of Envoronment (1 992).

36 General introduction

Table 5. The vanous applications of resins in which PBDE are used are listed below8

Polymer Pnncipal applications Examples of final products

ABS Moulded parts TV-sets/business machmes, computer housings, household appliances (hairdryer, curler). automotive parts, electromcs, telecommunications

EPOXY C1rcu1t boards, Computers, sh1p Interiors, protective coatings electronic parts

PAINTS/ Coatings Marine and industry lacquers LACQUERS for protection of containers

PHENOLICS Printed circuit boards Paper laminates/glass prepregs for printed c1rcuit boards

PAN Panels, electrical Lighting panels for elevators components and rooms, housmg of electncal appliances

PA Electncal connectors, Computers, connectors, automatlve interior housing in electrical mdustry, parts board, electncal connectors, automotive industry, trans­ portation

PBT Electrical connectors Switches, fuse, sw1tch box, and components computer housings, switch­ board electncal connectors, stereos, business machines, military electromcs

PE/XPE Cross-linked w1re and Major application: power cable cable, foam tubmg, with cross-linked low density weather protection PE; also used for conduit for and m01sture barriers building With high dens1ty PE; Fmal uses: portable apparatus bu1ldmg control, Instrument, shipboard, automotive, manne appliances, 1nsulat1on of heatmg tubes

PET Electncal Boxes, relays, coils, bobbms components

37 EHC 162: Brominated diphenyl ethers

Table 5 (contd)

pp Conduits, electromc TV and electromc dev1ces, such dev1ces as yoke, housmgs, c1rcuit board hangers, condu1ts; Fmal uses: electro-mechamcal parts TV, hot waste water p1pes, underground )Unction boxes

PS, HIPS TV cabmets and back TV back panels, computer covers, electrical covers and housmgs of appliance housmgs electr~cal appliances, off1ce machmes, smoke detectors

PVC Cable sheets W1re and cables, floor mats, mdustr~al sheets

PUR Cush1omng materials, Furn1ture, sound msulat1on packaging, paddmg panels, wood 1mitat1ons, transportation

RUBBER Transportation Conveyor belts, foamed p1pes for msulat1on

TEXTILES Coatmgs Back coatmgs, 1mpregnat1on: carpets, automotive seatmg, furniture 1n homes and off1c1al buildmgs, aircraft, under­ grounds, tents, tra1ns, anci military safety clothmg

UPE C1rcu1t boards, Electrical equ1pment, coatings coatmgs for chemical processing plants mouldmgs, military and mar1ne applications: construction panels

8 From: EBFRIP (1990).

38 3. FORMATION OF BROMINATED DIBENZOFURANS AND DIBENZODIOXINS FROM POLYBROMINATED DIPHENYL ETHERS

3.1 General

Polybrominated dibenzofurans (PBDF) and polybrominated dibenzodioxins (PBDD) can be formed from polybrominated diphenyl ethers, polybrominated phenols, and polybrominated biphenyls under different conditions, including heating (combustion). Laboratory experiments have also demonstrated the formation of PBDF and PBDD during the pyrolysis of certain other brominated flame retardants (see the EHC on Brominated flame retardants, in preparation). As discussed in EHC 88: Polychlorinated dibenzo-para-dioxins and dibenzofurans, there are hundreds of possible congeners of halogenated dibenzofurans and dibenzo-dioxins. However, only congeners with substituents in the 2,3, 7 ,8-positions are of toxicological significance. In many reports, only the total levels of PBDF and PBDD are given, without regard to substitution pattern; such totals are of limited value in the estimation of possible risk. Hutzinger & co-workers investigated the pyrolysis of brominated flame retardants and flame retardant polymer systems and several publications have appeared. In general, the results reported showed that brominated dibenzofurans were observed at 700-800 oc and that the 2,3, 7 .8-substituted compounds were seen in only low concentrations, if at all (Thoma et al., 1987a,b; Thoma & Hutzinger. 1987; Dumler et al.. 1989). Short! y after the initial reports of Buser and Hutzinger, BFRIP and German chemical companies (Bayer, BASF, and Hoechst) and American industries independently reported the results of combustion and pyrolysis experiments with flame retarded polymers (BFRIP. 1990). Recent! y, brominated aromatic compounds have also attracted attention. since reports have appeared about emissions of PBDD and PBDF and other brominated and mixed halogenated aromatic compounds in accidental fires and from the combustion of waste (see section 4 of both DeBDE and OBDE).

39 EHC 162: Brominated diphenyl ethers

For more information on these pyrolysis experiments, see the different sections relating to the individual brominated diphenyl ethers, e.g., PeBDE, OBDE, and DeBDE. As an example, the formation of PBDF and PBDD from decabromodiphenyl ether is illustrated in Fig. 1.

- nBr• ~0~ 1 Br,. ~r ~ 0

+(0) ~ ~ Br,. Br,

+ ( H l (c)(" 0 "1'01 - HBr PBDF f'?>i .. ~~""\ "' ''· ,,, ~

+ ( H l o·H: ...... a;.:@ : - 2 H8r • 'a·;··i-io Br,. : ...... : Br Br,. Br, 1

PBDD

F1g. 1. Poss1ble mechan1sms for the format1on of PBDF and PBDD from decabromod1phenyl ether. From: B1enek et al. (1989).

40 General introduction

3.2 Additional data on the pyrolysis of non-specified PBDE and/or polymers containing non-specified PBDE

The earliest published work on the pyrolysis of brominated flame retardants was that of Buser, whose first paper appeared in 1986 (Buser, 1986). Buser pyrolysed three technical PBDE mixtures with different degrees of bromination from commercial sources (pentabromo-, 71% bromine; octabromo-, 79% bromine (predominantly hexa- to nonabrominated PBDE) and decabromo-, 83% bromine, 97% DeBDE) at 510-630 oc in small quartz vials. The vials were placed in a heated oven for about one minute, and the contents analysed. A range of PBDD and PBDF was found with a total yield of up to 10%. HRGG/MS analysis revealed the formation of reasonably simple mixtures of reaction products with often one or two main PBDF- and PBDD-isomers. Debromination reactions lead to lower brominated PBDF and PBDD congeners. In general, the higher brominated PBDE lead to higher brominated PBDF and PBDD. Most likely, the PBDF and PBDD are formed in intramolecular cyclization reactions involving the attack by oxygen on the diphenyl ether system (Fig. 1) (Buser, 1986; Bieniek et al., 1989). The next report to appear in the literature was also in 1986 from the laboratory of Hutzinger. Hutzinger's group pyrolysed penta- and decabromodiphenyl ethers at 700, 800, and 900 oc. in a quartz tube oven, for about 10 min. They did not provide any isomer-specific results, but they reported the formation of PBDF and PBDD. Hutzinger continued to investigate the pyrolysis of brominated flame retardants and brominated flame retardant polymer systems, and several publications appeared (Thoma et al., 1987a,b; Thoma & Hutzinger, 1987; Dumler et al., 1989a). In general, the results reported in these publications were consistent with those of earlier work in that maximum concentrations of PBDF were observed at 700-800 oc and 2,3, 7 ,8-substituted compounds were seen only in very low concentrations, if at all. Shortly after the initial reports of Buser and Hutzinger, BFRIP and German chemical companies (Bayer, BASF and Hoechst) independently reported the results of combustion and pyrolysis experiments with flame retarded polymers.

41 EHC 162: Brominated diphenyl ethers

In the German work, pyrolysis studies were conducted with high-impact polystyrene/DeBDE, polypropylene/DeBDE, and ABS/OBDE (Neupert et al., 1989) (see also individual flame retardants). In all of these studies, the pyrolysis residues were analysed for the presence of PBDD and PBDF. While brominated PBDF were identified, only very small quantities of 2,3,7,8- TeBDF were observed (see Table 6) (BFRIP, 1990).

Table 6. Analytical results from the pyrolysis products of ABS/OBDE (Bayerl 8

Compound Concentration

Test 1 (ppml Test 2 (ppml

Brominated d1benzodioxms

Brommated dibenzofurans:

MBDF 115 60

10 000 7500

TrBDF 8000 2500

TeBDF 2000 2500

2,3,7,8-TeBDF < 0.1 < 8

PeBDF 1700 2000

HxBDF 530 470

HpBDF <1.4 32

OBDF < 3 < 2.5

8 From: BFRIP ( 19901. bND = Not detectable.

Other brominated pyrolysis products of PBDE may be formed by cleavage and oxidation, including PBBz, phenol, and some naphthalenes. PBDF, however, may also be formed from small reactive species generated during PBDE cleavage (Umweltbundesamt, 1989; Buser, 1986) (see also the individual brominated diphenyl ethers).

42 General introduction

Table 7. Thermal decompos1t10n products from a m1xture of two commercial PBDE (1 :1 w/w)8

Product Max1mum y1eld (%)

N1trogen (650 ° C) A~r (625 °C)

Dibromobenzenes 0.35

Tnbromobenzenes 0.64 0.92

Tetrabromobenzenes 0 43 0.95

Unknown (pentabromobenzenes7) 0.04 0.24

Brommated alkanes, alkenes, 1 40 0.77 and other PICsb

D1BDF 0.03

TrDBF 0 03 0.03

TeBDF 0.03 0.03

D1BDD 0.04

TrBDD 0.04

TeBDD 0.01

8 From: Stneb1ch et al. ( 1 991 ). bPICs = Products of Incomplete combust1on. eND = Not detectable.

Striebich et al. ( 1991) examined gas phase oxidative and pyrolysis thermal decomposition of a 1:1 percentage weight mixture of two commercial polybrominated diphenyl ether products (tri- through deca-bromination). The gas phase material was quantitatively transported to a quartz thermal reactor and subjected to a series of controlled time/temperature exposures (300-800 oc for 2.0 seconds) in either air or a nitrogen atmosphere. Thermal decomposition products were identified. Isomers with higher levels of bromination were generally more stable than lower brominated diphenyl ethers, under both oxidative and pyrolytic conditions. Table 7 shows the approximate yields of products from hrominated diphenyl ethers. At 800 oc. all products were decomposed to HBr or non-detectable products, in both air and nitrogen. Neither PBDF/PBDD nor any parent material could be detected at this temperature.

43 4. WORKPLACE EXPOSURE STUDIES

4.1 Exposure to PBDE

Inhalation exposure to brominated diphenyl ethers is expected to be low, since the vapour pressure of these chemicals is in the range of IQ-7 mmHg. Particulates in the respirable range are expected to be formed during the grinding of solids. As inhalation of dust is possible, the use of dust respirators and gloves/goggles is recommended in areas of potential exposure. Dermal exposure may occur during filtration, drying, drumming/bagging, size reduction, and maintenance (US EPA, 1986). Exposure to these compounds can also take place during processing (incorporation into various polymers) and the use of the polymer blend to fabricate the final articles. After processing, the resin is generally in the form of pellets rather than powder. Exposure is expected to be low at fabrication sites because of the low vapour pressure and of ventilation controls (US EPA, 1986).

4.2 Exposure to PBDF/PBDD

Workers may be exposed to PBDF/PBDD during the production and processing of plastics containing PBDE as flame retardants and of products made from them. In addition, wcrkers and the general population may be exposed to PBDF/PBDD when products, particularly from the electrical, electronic, and computer industries, emit PBDF /PBDD during normal operations (see section 4 of both DeBDE and OBDE). The PBDF/PBDD contents of component parts taken from 6 electrical appliances (including printers, TV sets, and computer terminals) as well as two casings were determined. PBDF/PBDD were detected in 16 of the materials; mainly higher brominated PBDF at concentrations of between 0.007 and 4.2 mg/kg (sum of MBDF to HxBDF/MBDD to HxBDD) were found (Hamm & Thiesen, 1992).

44 General introduction

Determination of PBDE and PBDF concentrations in air and dust samples were made in offices having a large number of TV or computer monitors in operation: the police traffic control office in 2 Hamburg (47 monitors; room 100 m , 6 m high, 23 oq and three rooms of a television company with monitors (20 °C). In the police traffic control office, air samples were taken for 3 days at a level of 1.5 m above the floor, a total of 84 m3 air being drawn, and analysed. Dust samples were taken from the monitors from a total surface of 3 x 10 m (39 g). 2 In the first room of a television company (50 m ), where 58 monitors were in use, a total of 129 m3 air was taken over 5 days. In the second room (40 m2),where 38 monitors were in use, 3 2 126 m air was taken, while in the third room (30 m ), where 42 monitors were in use, 145 m3 air was taken. Dust samples were also collected once a day from all rooms using a vacuum cleaner. The concentrations in air of the police station and the television company ranged between 0.29 and 1.27 pg PBDF/m3 3 and 97 pg PBDE/m . Indoor dust contained PBDF at low ppb and PBDE at high ppb levels. 2,3,7,8-substituted PBDF were not detected (limit of determination between 0.3 and 0.1 pg/m3) (Ball et a!., 1992).

45 5. EXPOSURE OF THE GENERAL POPULATION

5.1 General population

Limited information is available on the exposure of the general population to brominated diphenyl ethers. Uptake of TeBDE and PeBDE may occur in humans via the foodchain, e.g., by consuming fish. In Germany, PBDE has been detected in human and cow's milk at levels of 2.6 and 3 J.tg/kg fat, respectively (Kruger, 1988). Remmers et al. ( 1990) found evidence of the occurrence of polychlorinated diphenyl ethers (PCDE) and PBDE in human adipose tissue specimens from the USA, during the analysis of these tissues for dioxins and furans. The results showed the presence of HxBDE/HxCDE through to DeBDE/DeCDE in the tissues analysed. The presence of brominated diphenyl ethers was indicated in all of the 47 samples analysed (Cramer et al.. 1990a,b). The human samples were composites derived from all parts of the USA and covering ages ranging from birth to > 45 years. Additional work is needed to confirm the presence of these compounds, which have been found provisionally in the following frequencies and concentrations; HxBDE (72%; nd-1000 ng/kg); HpBDE (100%; 1- 2000 ng/kg) and OBDE (60%; nd-8000 ng/kg). DeBDE was found in only a few samples at concentrations of 0.4-0.7 ng/kg. Exposure may also mainly occur through skin contact (tlame retardants in polymers used in textiles), but also via inhalation (release of flame retardants from the polymer matrix) (US EPA, 1986).

5.2 Possible exposure to PBDE and PBDF/PBDD

5.2. 1 Television sets

Studies were carried out to determine whether PBDF escape from TV sets. Four air samples (2 parallel to each other) were 3 taken over 3 days in a closed room (volume 26.8 m ), where a new TV set was operating for 17 h/day. The surface temperature

46 General introduction

of the TV set (back panel) was 38-40 °C. One sampling was performed above the TV set, while the others were carried out in the centre of the room (2.2 m from the TV set). The levels in the centre of the room of tri-, tetra-, penta-, and hexabromo­ dibenzofurans were 25, 2. 7, 0.5, and 0.1 pg/m3, respectively 3 (levels in outdoor air ranged from < 0.05 to 0.16 pg/m ). Above the TV set, the concentrations of the 4 PBDF were 143, 11, 0.5, 3 and < 0.1 pg/m . Hepta- and octabromodibenzofuran, and poly­ brominated dibenzodioxins were not found (limits of determination 3 0.1 and 0.2 pg/m , respectively) (Bruckmann et al., 1990). An investigation was conducted to determine the emissions of PBDE and PBDF from plastics in two TV sets, one colour and one monochrome, two computer monitors, and three printers, under conditions of use. Analytical methods were refined to obtain a reliable determination of PBDF. Each appliance was placed, under conditions of use, in a test chamber. The volume of the steel chamber was 1.17 m3 (1.5xl.07x0.82 m). For three days, pure air was continuously drawn through the chambers at a rate of 1.5 m3/h; the emitted compounds were absorbed on a sampler for the subsequent extraction and determination of PBDE and PBDF with 4 or more bromines. PBDF concentrations were found to vary between not detected (limit of detection 3-10 pg) and 1799 pg per appliance tested and PBDE concentrations, between 0.4 and 889 ng/appliance; 2,3,7,8 isomers (1070 pg/appliance) were detected only from the colour TV set (Ball et al., 1991). Three new television sets were placed in a 1. 81 m3 test chamber. Two of the cabinets were made from polystyrene, which was t1ame retarded with 11.5% DeBDE. The third television set

was made of high-impact polystyrene, treated with DeBDE/Sb20 3 as a tlame retardant. PBDF and PBDD concentrations were determined in air collected over 3 days while the two television sets were operating and during one day when the third TV set was operating. The concentrations of TeBDD, PeBDD, TeBDF, and PeBDF ranged between 0.09 and 1.52 pg/m3 (Ranken et al.,1990).

5. 2. 2 Fire tests and fire accidents

Six appliances and 2 casings were burned in a fire test room 2 3 (tloor area 21 m , volume 48 m ), which was kept closed during the fire tests and slowly ventilated after extinguishing the fires

47 EHC 162: Brominated diphenyl ethers

(worst case conditions). After the fire test, samples of combustion residues and smoke condensate were taken. Smoke was collected in 5 tests. The combustion residues showed the presence of PBDF and PBDD in concentrations ranging between 1 and 1930 mg/kg and from the casing components almost 1%. Smoke condensate from contaminated surfaces contained levels of between 6 and 1610 p,g monobromo- up to hexabromodibenzofuran/dibenzodioxin 2 per m . Smoke contained 11-1700 p,g monobromo- up to hexabromo- dibenzofuran/dibenzodioxin per m3 (see Table 8) (Hamm & Theisen, 1992). Residues and smoke condensates resulting from actual fire accidents with 9 TV sets were examined. PBDF/PBDD concentrations in the residues were mainly in the p,g/kg range, one value being 107 mg/kg. Close to the fire site, the PBDF/PBDD area contamination concentrations were between 0.1 and 13.1 p,g/m3 (see Table 9) (Hamm & Theisen, 1992). It was concluded that the levels of PBDF/PBDD produced in real fires are much lower than those produced under fire-test conditions.

48 Table 8. PBDF/D concentrations 1n ongmal components of electrical appliances and 1n samples from fire tests with these appliances or with their casmgs8

Object of mvest1gat10n Ongmal components Fire test samples

Casings Printed c1 rcUit Combustion Smoke Smoke boards res1dues condensate

Total mono· to Total mono· to Total mono- to Total mono- to Total mono-to hexaBDF/D Jlg/g hexaBDF/D Jlg/g hexaBDF/D hexaBDF/D hexaBDF/D (ppm) (ppm) Jlg/g (ppm) Jlg/m2 Jlg/mJ

Casmg of electncal appliance 1 0.63 b 8700 177 b

Casmg of electncal appliance 2 0.64 b 7750 1610 b

Electncal appliance 3 c 1.77 468 106 456

Electncal appliance 4 0.06 3.44 43 260 355

Electrical appliance 5 0.81 1.98 18 396 1700

Electncal appliance 6 4.20 0.35 1930 234 1350

Electrical appliance 7 c 0.13 1 6 11

Electrical appliance 8 1.26 0.007 24 323 -b

8 From: Hamm & Th1esen (1992). b = Not determmed. c = Not detectable. c.o-1::.. EHC 162: Brominated diphenyl ethers

Table 9. PBDF/D-concentrat1ons in residues and smoke condensates from real f1re accidents with television sets"

F1re accident Combust1on Smoke condensates (Case number) residues

Close to f1re s1te At some d1stance from fire site

Total mono- to Total mono- to Total mono- to hexaBDF/D hexaBDF/D hexaBDF/D Jlg/g (ppm) Jlg/m' Jlglm'

0.235 10.7 0.665

0.004 0.134 0.102

Ill 0.209 13.1 0.382

IV 0.009 NDb NOb

v 0.001 4.82 1.39

VI 0.017 0.759 0.425

VII 0.001 0.021 0.008

VIII 0.001 10.5 5.37

IX 107 7.47 0.847

8 From: Hamm & Thiesen (1992). bND = Not detectable.

50 6. ENVIRONMENTAL POLLUTION BY PBDE

6.1 Ultimate fate following use

Products containing PBDE are disposed of in the normal domestic waste stream (landfill and incineration). No studies are available on the fate of PBDE-containing products in landfills, but there is concern that the PBDE may eventually leach out. Bearing in mind that PBDE, at least the congeners with more than 3 bromine atoms, are persistent in the environment, the introduction of such chemicals into widespread products may be a considerable long-term diffuse source of emissions of these compounds to the environment. This type of source is difficult to control and the unnecessary use of persistent organic compounds should be avoided. Formation of PBDF and/or PBDD as a result of landfill fires is also a possibility, though no data are available on the scale of this source. The results of pyrolysis experiments showed that PBDE can form PBDF and PBDD (in much smaller quantities) under a wide range of heating conditions (see General Introduction sections 3.1 and 3.2). If chlorine is present, mixed halogenated furans/dioxins can also be generated (Oberg et a!., 1987; Zier et a!., 1991). Unless sufficiently high temperatures and long residence times are maintained, PBDF/PBDD can be generated during the incineration of products containing PBDE. They can also result from poorly-controlled combustion gas cooling. Modern, properly operated municipal waste incineration (MWI) should not emit significant quantities of PBDF/PBDD, regardless of the composition of the municipal waste. Lahl et a!. (1991) reported increases in dibenzofuran and dibenzodioxin levels in tilter dust, when products containing PBDE were added to the feed-stock. Riggs et a!. (1990) reported PBDF generation when a flame retarded resin was burnt under simulated MWI conditions. However, Oberg et a!. (1987) reported no increased emissions of dibenzodioxins when the bromine content of an incineration feed-stock was increased. Monobromodichloro­ dibenzofuran levels were slightly increased. Oberg & Bergstrom (1990) conducted further experiments with a hazardous waste

51 EHC 162: Brominated diphenyl ethers

mcmerator, to study the relationship between bromine levels in municipal waste and incinerator dibenzodioxin and dibenzofuran emissions. They concluded that no unacceptable environmental risks were associated with the incineration of brominated compounds in plants with good combustion conditions equipped with efficient flue gas cleaning. They further noted that only 0.0125% of the feed to Swedish MWis was brominated waste.

6.2 Air

Watanabe et al. (1992) reported on the presence of PBDE in the air in Taiwan and Japan. The concentrations in the air samples collected in Taiwan from a recycling plant in January 1991 were, in general, higher than those in Japan; 3 samples were analysed in Taiwan, and 5 in Japan. Tribromo-, tetrabromo-, pentabromo-, and hexabromodiphenyl ethers were present in the following mean 3 concentrations: Taiwan, 32, 52, 23, and 31 pg/m , and, Japan, 3 7.1, 21, 8.9, and 21 pg/m , respectively.

6.3 Soil

Two ash and two soil samples were collected in Taiwan from a recycling plant in January 1991 and analysed for the presence of PBDE. Tri-, tetra-, penta-, hexa-, and decabromodiphenyl ethers were present in ash in the following concentrations 20-20, 130, 78-110, 47-54, and 510-2500 J.Lglkg, respectively; the con­ centrations in soil were 38-40, 75-104, 41-84, 20-23 and 260-330 J.Lglkg, respectively. Hepta- and octabromodiphenyl ether were not found (Watanabe et al., undated).

6.4 Water

Marine, estuarine, and river water samples were analysed for the presence of the different PBDE. Except for monobromo­ diphenyl ether, levels of all the higher brominated PBDE were below the detection limit. MBDE was mainly found in the surroundings of manufacturing plants in the USA (US EPA, 1986).

52 General introduction

6.5 Sediments and sewage sludge

In Japan, Spain, Sweden, and the USA, studies were carried out to determine the presence of the different PBDE in marine, estuarine, or river sediment. PBDE were mainly found in river sediment. In general, the levels were below 100 J.Lglkg dry weight, except in rivers in the vicinity of manufacturing plants. In these cases, the concentrations were much higher. In a river in Sweden, concentrations of 11.5 mg DeBDE, 0.8 mg TeBDE, and 2.8 mg PeBDE/kg dry weight were found. In the USA, at a manufacturing plant, as much as 1 g DeBDE/kg was found (Zweidinger et a!., 1978; DeCarlo, 1979; Environment Agency Japan, 1983, 1989, 1991; Watanabe eta!.. 1986, 1987b; Fernandez eta!., 1992). The upper layers in a laminated sediment core from the Baltic Sea (Bornholm Deep) contained higher levels of TeBDE and PeBDE than the deeper layers, indicating an increasing burden of these compounds (Nylund et a!., 1992). A series of samples of sewage sludges from municipal waste water treatment plants in Germany were analysed for poly­ halogenated compounds, such as halogenated diphenyl ethers. Tribromo- to heptabromodiphenyl ethers were found at relatively high concentrations (Hagenmaier et a!., 1991). Sewage sludge was analysed in Sweden for the presence of TeBDE and PeBDE. Concentrations of 15 and 19 J.Lglkg, respectively, were found (Sellstrom eta!.. 1990a,b).

6.6 Aquatic vertebrates

The presence of PBDE depends mainly on the degree of bromination. DeBDE, OBDE, and HxBDE were not found in mussel and fish samples collected in Japan. No data are available for HpBDE. However, PeBDE was found in mussel and fish species in concentrations of < 3 J.Lglkg wet weight in Japan. Concentrations of 22 J.Lg 2,2' ,4,4' ,5-PeBDE/kg wet weight were found in cod liver collected in the North Sea, and concentrations of up to 64 J.Lglkg on a fat basis were found in fish collected in Sweden. The concentrations were much higher in fish collected in the vicinity of industrial areas, e.g., up to 9.4 mg/kg on a fat basis (Jansson et a!., in press). Levels for TeBDE, mainly 2,2',4,4'-

53 EHC 762: Brominated diphenyl ethers

TeBDE, were comparable but generally higher. Mussels and fish in Japan contained up to 14.6 11g/kg wet weight, cod liver collected in the North Sea, 360 j.tg/kg, and eel from the Netherlands, up to 1700 J.tg/kg fat. Different species of fish col­ lected in Sweden contained up to 88 mg/kg fat (Andersson & Blomkvist, 1981; Watanabe, 1987; Watanabe et al., 1987b; De Boer, 1989, 1990). An increasing trend was observed in PeBDE and TeBDE levels in freshwater fish in Sweden. Only limited data are available concerning lower brominated PBDE (Jansson et al., in press). Thirty-five samples of 18 freshwater fish collected in German rivers, and 17 samples collected from the Baltic Sea and the North Sea contained 18.2-983.6 and 0.6-119.9 J.tg PBDE/kg fat (deter­ mined as Bromkal 70-5DE), respectively (Kruger, 1988).

6. 7 Aquatic mammals

Three bottle-nose dolphins (Tursiops truncatus), collected during the 1987/88 mass mortality event along the central and south Atlantic coast of the USA, were analysed for brominated diphenyl ethers. The concentrations of PBDE were 200, 220, and 180 J.tg/kg lipid (Kuehl et al., 1991). Limited data are available on the presence of PBDE in aquatic mammals. 2,2'4,4'5-PeBDE was found in ringed and grey seals, collected in Sweden, in concentrations of 1. 7 and 40 J.tg/kg fat, respectively. TeBDE, mainly 2,2',4,4'-TeBDE, was also found in the blubber of these 2 species in concentrations of 47 and 650 11g/kg fat, respectively (Jansson et al., in press). Seals collected at Spitzbergen contained approximatey 10 J.tg PBDE/kg fat, determined as Bromkal 75DE (Kruger, 1988).

6.8 Terrestrial vertebrates

Pooled samples of rabbits, moose, and reindeer, collected in Sweden, contained PeBDE and TeBDE in concentrations of < 0.3, 0.64, and 0.26 J.tg 2,2',4,4',5-PeBDE/kg and < 2, 0.82, and 0.18 J.tg 2,2',4,4'-TeBDE/kg lipid, respectively (Jansson et a\., in press).

54 General introduction

Four samples of cow's milk were analysed in Germany for the presence of PBDE. The average concentration was 3.572 J.tg/kg fat (range 2.536-4.539 J.tg/kg) determined as Bromkal 70-SDE. The main component was HxBDE (Kruger, 1988).

6.8.1 Birds

Limited data are available on the presence of PBDE in birds. In Sweden, 2,2' ,4,4' ,5-PeBDE was found in the muscle tissue of osprey, in newborn starlings, and in guillemot eggs in concentrations of 140, 2.3-4.2, and 24-260 J.tg/kg lipid, respectively. A trend towards increasing concentrations of PeBDE and TeBDE in guillemot eggs from the Baltic Sea was observed. 2,2',4,4'-TeBDE was found in the muscle tissue of osprey in concentrations of up to 1800 J.tglkg. Guillemots collected from the Baltic Sea, the North Sea, and Spitzbergen contained 370, 80, and 130 J.tg/kg on a fat basis, respectively (Jansson et al., 1987, 1993). In the USA. indications were found that dibromodiphenyl ether was present in the eggs of fish-eating birds, but it was not quantified (Stafford. 1983).

6. 8. 2 Humans

In Germany. 25 samples of breast milk were analysed for the presence of PBDE. The ages of the women ranged between 24 and 36 years and most of them were breast-feeding their first or second child. The samples contained 0.6-11.1 llg PBDE/kg fat, deter­ mined as Bromkal 70-SDE. The main component was HxBDE. One sample from a Chinese woman showed 7. 7 llg PBDE/kg fat; a sample from another woman. exposed occupationally to hydraulic tluids and tranformer oils, contained 50 J.tg PBDE/kg fat. This last value was excluded frc"TI the given range and average. (Kruger, 1988).

55

DECABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS, AND RECOMMENDATIONS

1.1 Summary and evaluation

1. 1. 1 Identity, physical and chemical properties

Typically, commercial DeB DE has a purity of 97-98%, with 0.3-3.0% of nona- and/or octabrominated diphenyl ethers. Nonabromodiphenyl ether (NBDE) is the major impurity. In contrast to the other polybrominated diphenyl ethers there is only one isomer of DeBDE. The melting point of DeBDE is approximately 300 oc and decomposition occurs above 400 °C. Solubility in water is 20-30 f!gllitre and the log of the n-octanol/water partition coefficient is greater than 5. Vapour pressure is < 10· 6 mmHg at 20 °C.

1. 1.2 Production and uses

Among the brominated diphenyl ethers (mono- to deca-), deca­ bromodiphenyl ether is the most important commercial product with regard to production and use. Commercial DeBDE has been produced in increasing degrees of purity since the late 1970s. The global production of DeBDE is approximately 30 000 tonnes/year. It is used as an additive flame retardant in many plastics. especially high-impact polystyrene, and in the treatment of textiles used in soft furnishing, automobile fabrics, and tents.

1. 1.3 Environmental transport, distribution, and transformation

Photodegradation of DeBDE occurs in organic solvents under ultraviolet radiation (UVR) or sunlight; lower brominated diphenyl ethers and brominated dibenzofurans are formed. Photodegra­ dation also occurs, to a lesser extent, in water with sunlight; however, lower brominated diphenyl ethers and brominated di­ benzofurans have not been found.

59 EHC 162: Brominated diphenyl ethers

Levels of DeBDE extracted from polymers are close to, or below, the limit of detection, depending on the polymer type and extraction solvent. Because of its extremely low water solubility and vapour pressure, DeBDE is likely to be transported primarily by adsorption to particulate matter. It is persistent and likely to accumulate in sediment and soil. No data are available on its bioavailability from sediment and soil. A study on rainbow trout did not show any bioaccumulation in flesh, skin, or viscera, over 48 h. DeBDE is unlikely to bioaccumulate because of its high relative molecular mass. Products containing commercial DeBDE will eventually be disposed of by landfill or incineration. DeBDE may eventually leach from landfills. Polybrominated dibenzofurans (PBDF) and mixed halogen-dibenzofurans and -dibenzodioxins may result from landfill fires and inefficient incineration. Products containing commercial DeBDE may contribute to these emissions. Pyrolysis of both commercial DeBDE itself and polymers (HIPS, PBT, industrial polypropylene) containing DeBDE, in the presence of oxygen, produced PBDF, polybrominated dibenzodioxins (PBDD) being found to a lesser extent. The maximum formation of PBDF occurs at 400-500 °C, but it can occur at temperatures up to 800 oc, and S~03 plays a catalytic role in the formation of PBDF and PBDD. The formation, and amounts found, of PBDF and PBDD depend on temperature, oxygen content, and length of pyrolysis. In the absence of oxygen, mainly polybromobenzenes and polybromonaphthalenes are formed.

1. 1.4 Environmental levels and human exposure DeBDE has been identified in air in the vicimty of 3 manufacturing plants at concentrations of up to 25 11-g/m . DeBDE was not detected in water samples collected in Japan in the period 1977-91. However, it was detected in river and estuarine sediment, collected in Japan in the same period, at concentrations of up to approximately 12 mg/kg dry weight. DeBDE (up to 1 g/kg) was also found in the USA in river sediment close to one manufacturing plant. DeBDE was not detected in fish samples

60 Decabromodiphenyl ether

collected in Japan, but, in one mussel sample, a level just above the level of detection was found. DeBDE was not detected in human adipose tissue samples collected in Japan, but, in the USA, DeBDE was found in 3 out of 5 samples of buman adipose tissue. Human exposure to DeBDE can occur in the course of manufacture and formulation into polymers. Exposure of the general population to DeBDE is insignificant. Determination of occupational exposure to the breakdown products of DeBDE during manufacture, formulation, or use, showed that air samples close to the extruder head contained high concentrations of PBDF. Lower levels were found in the air of the workroom. PBDF was also found in wipe samples. The application of good engineering techniques has been shown to reduce occupational exposure to PBDF. Exposure of. the general population to PBDF impurities in flame retarded polymers is unlikely to be of significance.

1. 1.5 Kinetics and metabolism in laboratory animals and humans

DeBDE is poorly absorbed from the gastrointestinal tract and is rapidly excreted following injection. The results of metabolic studies on the rat, using 14C labelled DeBDE, indicated a half-life for the disappearance from the body of less than 24 h and that the principal route of elimination following oral ingestion was via the faeces. No appreciable 14C activity (less than 1%) was found in either urine or expired air. Rats fed 0.1 mg/kg body weight per day, for up to two years, showed no accumulation of DeBDE in serum, kidneys, muscle, or testes, as estimated from total bromine determination. Bromine accumulation in the liver plateaued at 30 days and was cleared within 10 days following treatment. After 180 days of treatment, the bromine level in the liver of treated rats was no greater than that in control rats. Adipose tissue accumulated low levels of total bromine, which remained after 90 days of clean diet; the nature of the retained "bromine" is not known. Since DeBDE accounted for only 77% of the commercial mixture used, "bromine" could have been derived from NBDE or OBDE.

61 EHC 162: Brominated diphenyl ethers

1. 1.6 Effects on laboratory mammals and in vitro test systems

The acute toxicity of DeBDE for laboratory animals is low. The substance is not an irritant to the skin or eyes of rabbits. It is not chloracnegenic on the skin of rabbits and is not a human skin sensitizer. The combustion products of flame retarded polystyrene containing DeBDE and Sb20 3 were tested for acute toxicity and

comedogenicity. The rat oral LD50 of the soot and char was > 2000 mg/kg body weight. In short-term toxicity studies on rats and mice, DeBDE (purity > 97%) at dietary levels of 100 g/kg (4 weeks) or 50 g/kg (13 weeks; equivalent to 2500 mg/kg body weight for the rat) did not induce adverse effects. A one-generation reproduction study on rats showed no adverse effects with dose levels of 100 mg/kg body weight. DeBDE did not cause any teratogenic effects in the fetuses of rats administered a dose level of 100 mg/kg body weight. With 1000 mg/kg body weight, malformations, such as delayed ossification, were seen. DeBDE was not shown to be mutagenic in a number of tests. In a carcinogenicity study on rats and mice. DeBDE (purity 94-99%) was administered at dietary levels of up to 50 g/kg. An increase in the incidence of adenomas (but not carcinomas) was found in the livers of male rats receiving 25 g/kg and female rats receiving 50 g DeBDE/kg. In male mice, increased incidences of hepatocellular adenomas and/or carcinomas (combined) were found at 25 g/kg and an increase in thyroid follicular cell adenomas/ carcinomas (combined) at both dose levels. Female mice did not show any increase in tumour incidence. There was equivocal evidence for carcinogenicity in male and female rats and male mice only at dose levels of 25-50 g DeBDE/kg diet. As the results of all mutagenicity tests have been negative. it can be concluded that DeBDE is not a genotoxic carcinogen. IARC (1990) concluded that there was limited evidence for the carcinogenicity of DeBDE in experimental animals. The very high dose levels, lack of genotoxicity, and minimal evidence for carcinogenicity indicate that DeBDE, at the present exposure levels, does not present a carcinogenic risk for humans.

62 Decabromodiphenyl ether

1.1.7 Effects on humans

No evidence for skin sensitization was found in 200 human subjects exposed to DeBDE in a sensitization test. A morbidity study of extruder personnel blending polybutyl­ eneterephthalate containing DeBDE, with consequently potential exposure to PBDD and PBDF for 13 years, did not reveal any deleterious effects, even though 2,3,7,8-TeBDF and -TeBDD were detected in the blood. Results of immunological studies showed that the immune system of the exposed persons was not adversely affected in 13 years.

1. 1.8 Effects on other organisms in the laboratory and field

The ECsoS for the growth of 3 marine unicellular algae were greater than 1 mg DeBDE/Iitre. No further information is available on the effects of DeBDE on other organisms in the laboratory and field.

1.2 Conclusions

1.2.1 DeBDE

DeBDE is widely used incorporated in polymers as an additive flame retardant. Contact of the general population is with products made from these polymers. Exposure is very low since the DeBDE is not readily extracted from polymers. The acute toxicity of DeBDE is very low and there is minimal absorption from the gastrointestinal tract. Thus, risk to the general popu­ lation from DeBDE is cor.sidered to be insignificant. Occupational exposure is to DeBDE in particulate form. The control of dust during manufacture and use will adequately reduce the risk for workers. DeBDE is persistent and binds to particulate matter in the environment; it is likely to accumulate in sediment. It is unlikely to bioaccumulate. Current evidence suggests that environmental photodegradation in water does not lead to the formation of lower brominated diphenylethers or brominated dibenzofurans, but Iittle is known about degradation in other media.

63 EHC 162: Brominated diphenyl ethers

There is minimal information on the toxicity of DeBDE for organisms in the environment.

1. 2. 2 Breakdown products

Formation of PBDF and, to some extent, PBDD may occur when DeBOE, or products containing it, are heated to 300- 800 °C. The possible hazards associated with this have to be addres~ed. Properly controlled incineration does not lead to the emission of significant quantities of brominated dioxins and -furans. Any uncontrolled combustion of products containing DeBDE can lead to an unquantified generation of PBDF/PBDD. The significance of this for both humans and the environment will be addressed in a future Environmental Health Criteria on PBDF/PBDD. PBDF have been found in the blood of workers involved in the production of plastics containing DeBOE. No adverse health effects have been associated with this exposure. Good engineering controls can prevent worker exposure to PBDF.

1 .3 Recommendations

1. 3. 1 General

• Workers involved in the manufacture of DeBOE and products containing the compound should be protected from exposure through the application of appropriate industrial hygiene measures. the monitoring of occupational exposure, and engineering controls.

• Environmental exposure should be minimized through the appropriate treatment of effluents and emissions in industries using the compound or products. Disposal of industrial wastes and consumer products should be controlled, to minimize environmental contamination with this persistent material and its breakdown products.

• Manufacturers should mm1m1ze levels of impurities in commercial DeBOE products, using the best available techniques. A purity of 97% or higher is recommended.

64 Decabromodiphenyl ether

• Incineration should only be carried out in properly constituted incinerators, running at consistently optimal conditions. Burning by any other means may lead to the production of PBDF and/or PBDD.

1.3.2 Further studies

• Further studies on the bioavailability and toxicity of sediment­ bound DeBDE should be performed on relevant organisms.

• Continued monitoring of environmental levels is required.

• The generation of PBDF under real fire conditions should be further investigated.

• Environmental biodegradation, and photodegradation in com­ partments other than water, should be further studied.

• Investigation into possible methods and consequences of re­ cycling of DeBDE-containing polymers should be made.

• Analytical methods for DeBDE in various matrices should be validated.

65 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2.1 Identity

2. 7. 7 Pure substance

Chemical structure:

6 0 6'

Br5 Br 5

Chemical formula: C12 Br10 0 Relative molecular mass: 959.22 Chemical name: decabromodiphenyl ether (DeBDE); decabromodiphenyl oxide CAS registry number: 1163-19-5 (61345-53-7, mixture of decabromodiphenyl oxide and

Sb 20 3) CAS name: 1, 1'-oxybis[2,3,4,5,6-pentabromo]­ benzene IUPAC name: bis(pentabromopheny!) ether EINECS registry number: 214604

66 Decabromodiphenyl ether

MITI number: 3-2846 Synonyms: decabromobiphenyl ether; decabromobiphenyl oxide; Decabrom; ether, bis(pentabromophenyl); ether, decabromodiphenyl

From: US EPA (1984); Ethyl Corp. (1992a).

On the basis of the chemical structure, decabromodiphenyl ether is fully brominated and there is only one congener.

2. 1.2 Technical product

Trade names: FR-300 BA; DE-83-RTM; Saytex 102; Saytex 102E; FR-1210; Adine 505: AFR 1021; Berkflam B10E; BRSSN; Bromkal 81; Bromkal 82-0DE; Bromkal 83-10 DE; Caliban F/R-P 39P; Caliban F/R-P 44; Chemflam 011; DE 83; DP 10F; EB 10FP; EBR 700; Flame Cut BR 100; FR 300BA; FR P-39; FRP 53; FR-PE; FR-PE(H); Planelon DB 100; Tardex 100: NC-1085; HF0-102; Hexcel PF1; Phoscon Br-250; NCI-C55287 Caliban-F/RP-44 is a DeBDE mixture with antimony oxide, and, F/RP-53 contains 60% DeBDE, which is used in conjunction with THP-salts finishes and an acrylic binder.

Commercial DeBDE is typically composed of 97-98% decabromodiphenyl ether with 0.3-3.0% other brominated diphenyl ethers (BFRIP, 1990) (see Table 1). Nonabromodiphenyl ether isomers are the major impurities. The commercial product typically contains a minimum of 81-83% bromine (IARC, 1990) (83% theoretical; Ethyl Corp. 1992a).

67 EHC 162: Brominated dipheny/ ethers

Differences in manufacturing processes affect the nature and amounts of impurities in the product (Larsen, 1980). Today's commercial product is considerably purer than that manufactured in the past. Isomers of nonabromodiphenyl ether and octabromodiphenyl ether have been reported as impurities in DeBDE (Timmons & Brown, 1988). FR-300-BA, produced in the early 1970s (no longer a commercial product), was composed of 77.4% DeBDE, 21.8% NBDE, and 0.8% OBDE (Norris et a!., 1975c). Later production of DeBDE, by the same manufacturer, ranged in composition from 94 to 99% DeBDE with 0.3-4.5% impurities (NBDE isomers were identified as the major impurities) (NTP, 1986). Other DeBDE products, e.g., DE-83, Saytex 102E, and Bromkal 82-0DE have a purity of approximately 93 to 98.5% with different quantities of impurities (Dow Chern. Comp., 1978; De Kok eta!., 1979; Davidson & Ariano, 1986). The availability of a technical product (possibly FR-1208) of 88.1% purity containing 11% nona-, and 0.5% octabromodiphenyl ether, and 0.1% hexabromobenzene has been reported (Klusmeier eta!., 1988). In Japan, a DeBDE is produced containing about 3% of nonabromodiphenyl ether as an impurity (Watanabe & Tatsukawa, 1987).

2.2 Physical and chemical properties

Commercial DeBDE is a free-flowing, odourless, off-white powder, with a bromine content of 81-83% and a high melting point. Melting point: 290-306 oc Decomposition point, > 320, > 400, and 425 oc DTA (different products) Volatility: 1% 319 oc TGA (% weight loss) 5% 353 oc 10% 370 oc 50% 414 oc 90% 436 oc Specific gravity: 3.0, 3.25 at 20 oc

68 Decabromodiphenyl ether

Vapour pressure: < 10-6 20 oc (mmHg) < 1 250 oc 2.03 278 oc 5.03 306 oc

Solubility: water 20-30 ~-tg/litre (at 25 °C) cottonseed oil 600 mgllitre saturated copra oil 920 mg/litre acetone 0.5, 1.0 g/litre benzene 1.0, 4.8 g/litre chlorobenzene 6.0 g/litre methylene bromide 4.2 g/litre methylene chloride 1.0, 4.9 g/litre a-xylene 8. 7 g/litre methanol 1 g/litre toluene 2 g/litre methyl ethyl ketone 1 g/litre pentane < 1 g/litre styrene < 1 g/litre Stability: stable under normal temperatures and pressures Flash-point: none Flammability: non-flammable Autoignition point: not applicable n-Octanol/water partition coefficient (log pOW): 5.24; 9.97*

From: Norris eta!. (1973, 1974, 1975a,c); Tabor & Bergman (1975); US EPA (1986); Chemag. (1988); Great Lakes Chemical Corporation (1990b); IARC (1990); Kopp (1990); Watanabe & Tatsukawa (1990)*; Bromine Compounds Ltd. (1992); Ethyl Corp. (1992a).

69 EHC 162: Brominated dipheny/ ethers

2.3 Analytical methods

The detection and quantification of DeBDE have been investigated by several authors. The methods are based on gas­ liquid chromatographic separation using different detection methods, such as electron capture detection and mass spectrometry (see General Introduction, section 2.1 and Table 2).

70 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

DeBOE has not been reported to occur naturally (see General Introduction, section 1.1).

3.2 Anthropogenic sources

3. 2. 1 Production levels and processes

DeBOE is produced by the bromination of diphenyl oxide in the presence of a Friedel-Crafts catalyst (Larsen, 1978). It is manufactured in a batch process in enclosed vessels during both the reaction and the drying cycle (US EPA, 1988; IARC, 1990). Commercial production of DeBOE in the USA began in 1976. Among brominated flame retardants, the quantities produced rank second only to the quantities of tetrabromobisphenol A. There are 2 manufacturers in the USA (BFRIP, 1992). IARC (1990) reported 2 manufacturers in Belgium, 1 each in Switzerland, the United Kingdom, and Israel, and 5 in Japan (US EPA, 1988). About 30 000 tonnes of DeBOE are used annually throughout the world. About 40% of this total is used (in combination with antimony trioxide) in high-impact polystyrene applications, such as television and radio cabinets. Textile applications, such as a polyester fibre additives and coatings for automobile fabric, tarpaulins, and tents account for about 900 tonnes (IARC, 1990; OECD, 1991; Arias, 1992). The annual consumption of DeBOE in Japan was 1000 tonnes in 1976, 2900 tonnes in 1984, 4000 tonnes in 1987, and 9800 tonnes in 1991, mainly used for polystyrene, polyester, and polypropylene (Watanabe, 1987; Watanabe et al., 1987b; Watanabe et al., undated). Recently published figures from a Japanese study showed that the consumption of PBDE (mainly DeBOE) in Japan was about 20-30% of the total consumption of brominated flame retardants (OECD, 1991).

71 EHC 162: Brominated diphenyl ethers

In the Federal Republic of Germany, 1800-2000 tonnes were used in plastics in 1988. DeBOE mixed with antimony trioxide and DeBOE used in conjunction with tetrakis (hydroxymethyl) phosphonium (fHP) salt finishes and an acrylic binder are used to blend 50150 and 65/35 with polyester/cotton (Ulsamer et al., 1980). An estimation of the use of decabromodiphenyl ether in the Netherlands in 1988 was 1100-1300 tonnes (Anon, 1989).

3.2.2 Uses

DeBOE is a non-reactive, additive flame retardant widely used for its high bromine content, thermal stability, and cost effectiveness. It is used in thermoplastic resins, thermoset resins, textiles, adhesives, and coatings. The major applications are for high-impact polystyrene, cross-linked polyethylene polybutyl­ eneterephthalate, glass-reinforced thermoset and thermoplastic polyester moulding resins, low density polyethylene extrusion coatings, non-drip polypropylene (homo and copolymers), acrylo­ nitrile-butadiene-styrene rubber (ABS), nylon, adhesives, epoxy resins, polyvinylchloride, and elastomers. The concentrations of DeBOE in the polymers range from 6 to 22% (fabor & Bergman, 1975; Flick, 1986; NTP, 1986; Kaart & Kokk, 1987; IARC 1990). A mixture of DeBOE and antimony trioxide has been used to treat nylon and polyester/cotton fabrics for industrial safety apparel and tents (LeBlanc, 1979). DeBOE is also used in the insulating materials for wire and electrical cable (IARC, 1990). In the United Kingdom, approximately 1000-1200 tonnes DeBOE is used per year in the textile industry (back coatings on synthetic fibres) (United Kingdom Department of Environment, 1992).

72 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

4.1 Transport and distribution between media

4. 1. 1 Extraction from polymers

Pellets of ABS (acrylonitrile-butadiene-styrene) terpolymer and polystyrene containing 10% DeBDE, were placed in 2 litres of water and shaken mechanically. Total bromine in water was estimated after 3 h and up to 187 h. Extraction of bromine took place from the ABS, during the first 43 h, in concentrations ranging from < 1.0 to 3.7 mg/litre. No bromine was extracted from polystyrene (limit of determination < 0.5 mg/litre). Because there was no increase in bromine concentration with time, it was suggested by the authors that the levels found were due to erosion and not to extraction. Extraction studies were also carried out under static conditions with pellets of ABS containing 4.25% DeBDE. Water, acetic acid, and cottonseed oil were used as extraction solvents at temperatures of approximately 50 or 60 °C, during 1 or 7 days. Extraction occurred only with cottonseed oil (7 days, 60 oq at 1 mg DeBDE!litre (limit of determination 0.075 mg/litre) (Norris et al., 1973, 1974, 1975a).

4.2 Biotransformation

No data are available.

4.3 Abiotic degradation

4. 3. 1 Photodegradation

Studies have been performed on the photodegradation of DeBDE in organic solvents and water. Organic solvents were used in the initial photodegradation studies because of the extremely low water solubility of DeBDE. In xylene, DeBDE was photodegraded by reductive debromination with a half-life of 15 h (Norris et al., 1973, 1975a).

73 EHC 162: Brominated diphenyl ethers

A commercial mixture of DeBDE containing traces of a nonabromodiphenyl ether, was irradiated in hexane solution with UVR and sunlight. A complicated mixture of tri- to octabromo­ diphenyl ether congeners was detected. Furthermore, a large number of PBDF containing 1-6 bromo atoms was formed. The yield of the PBDF under the experimental conditions was approximately 20% of the total amount of DeBDE, after 16 h of irradiation by UVR and approximately 10% by sunlight. The formation and distribution of photoproducts by sunlight were similar to those of UVR, though a few differences could be recognized in both, i.e., the decomposition rate of DeBDE and the total amount of, and kinds of, PBDF formed. Pol ybromobenzenes were also found in minor quantities in this experiment. The formation of PBDF appeared to occur secondarily from debrominated diphenyl ethers as photoproducts of DeBDE, but not directly from DeBDE (Watanabe & Tatsukawa, 1987). The xylene studies showed that DeBDE photodegraded readily, but did not provide any indication of the nature of the stability of the decomposition products of DeBDE in an aqueous environment. The proposed stepwise photoreduction of DeBDE in xylene could lead to the formation of lower brominated diphenyl ethers, which might be more stable to UVR. However, in water, photohydroxylation would be the favoured route and the hydroxyl substituted degradation products would decompose rapidly via increased UV absorption. This was demonstrated when DeBDE in water was exposed to actual sunlight over a 3-month period (10 g DeBDE in 8 litres of water). This study was conducted to determine whether stable lower brominated diphenyl ethers were formed that would show increased persistence over DeBDE. Analysis (by GC/MS) of the exposed water solution after 31, 66, and 98 days showed a significant increase in bromine concentration relative to the unexposed 98-day sampiP. After 98 days, the bromine concentration corresponded to the breakdown of about 300 times the initial amount of DeBDE soluble in water. Xylene extracts of the water phase of both 98-day samples were analysed using electron capture gas chromatography. Levels of 4-mono­ bromodiphenyl ether and 4,4'-dibromodiphenyl ether were quantified and found to be < 5 and < 2 ppb, respectively. In no case did the exposed sample show an increase in any peak, with

74 Decabromodiphenyl ether

retention times similar to those of the lower brominated diphenyl ethers. The products of the photodegradation of DeBDE in water are not lower brominated diphenyl ethers (Norris eta!., 1973, 1975a).

4. 3. 2 Pyrolysis

A commercial DeBDE, FR 300 BA (77% DeBDE), was heated in a quartz tube at 700, 800, and 900 oc and the concentrations of PBDD and PBDF determined. The residues contained tetra- to octabromodibenzofurans together with hepta­ and octabromo-dioxins; the optimal formation temperatures were 800 and 900 oc (Thoma et al., 1987a; Zacharewski et al., 1988). FR 300 BA (77%) was pyrolysed at 600, 700, 800, and 900 oc in the absence of oxygen in a SGE pyrojector and the residues were analysed using GC/MS in an on-line operation. Polybromobenzenes (PBB), polybromonaphthalenes (PBN), and polybrominated dibenzofurans were detected in the pyrolysate. Sixty percent of the starting products were decomposed at 600 °C, hexabromobenzene being formed as the main component together with traces of pentabromobenzenes and nonabromodiphenyl ether. At a higher temperature (700 °C}, the pentabromobenzene concentration increased and tetrabromobenzenes were also formed. Maximum amounts of hepta- and octabromodibenzofurans and hexabromonaphthalenes were produced at this temperature. At 800 oc and higher. an increase in levels of tetra- and penta­ bromobenzenes was observed. During these reactions, the C-0 bond is cleaved followed by the attachment of a bromine atom. C-C ring closure leading to dibenzofuran formation is very strongly suppressed by DeBDE (Thoma & Hutzinger, 1987, 1989). In the case of decabromodiphenyl ether (DeBDE), a total amount of 1-2% PBDF and PBDD was formed on thermolysis of DeBDE. At a temperature of 630 °C, 90% of DeBDE was decomposed. The major products were PBBz (tri- to hexa­ brominated). A heptabromodibenzofuran was a main product, though tetra- to heptabromodibenzofurans and tetra- to octa­ bromodibenzodioxins were also found. In these experiments, PBDF and PBDD were formed, which contained at least one or

75 EHC 162: Brominated dipheny/ ethers

two, respectively, bromine substituents less than the PBDE in the technical product; often the same major isomers were present (Buser, 1986).

4.3.3 Combustion of polymers containing DeBOE

4. 3. 3. 1 Pyrolysis studies

Clausen et al. (1987), Bieniek et al. (1989), and Lahaniatis (1989) studied the influence of the combustion temperature on the formation of PBDD and PBDF from plastics containing DeBDE. The results of the experiments with PBT with 10% DeBDE/6% Sb20 3 at temperatures of 400, 500, 600, 700, and 800 ac in the presence of air, showed the formation of PBDFs at mg/kg (ppm) concentrations. 2,3,7,8-TeBDD was not found with a limit of determination of 10 mg/kg. Maximum formation of TeBDF (4000 mg/kg) occurred at 400 ac, and, with increasing tempera­ ture, concentrations decreased. No PBDF were formed in the thermolysis of PBT with DeBDE but without Sb20 3 . The results are summarized in Table 10. Comparable experiments were reported by Lahaniatis et al. (1991). The formation of 2,3,7,8-tetrabromodibenzodioxin and - furan from various polymers with DeBDE or PBDE were studied in thermolysis experiments at 400, 600, and 800 °C. The polymers studied were PBT with 10% DeBDE with, or without, 6% Sb20 3, epoxide resin (ER) with 3-6% DeBDE, and phenol resin (PR) with 3-6% of PBDE and copper. The concentrations of the TeBDD and TeBDF at the 3 temperatures are given in Table 11. The 2,3,7,8-TeBDD concentrations ranged from 0.01 to 7 mg/kg and the 2,3,7,8-TeBDF concentrations from 0.01 to 52 mg/kg. The concentrations decreased with increasing tempera­ ture, and were low at 800 ac. Pure DeBDE and commercial polybutyleneterephthalate polymer samples containing DeBDE and antimony trioxide have been pyrolysed at temperatures ranging from 300 to 800 °C. The experiments were carried out in a vertical combustion apparatus. The polymer/DeBDE samples were: polybutylene-terephthalate (PBT) with 11% DeBDE and 5.5% Sb20 3, PBT with 9% DeBDE and 7% Sb20 3, and PBT with 11% DeBDE and 2.7% Sb20 3 (Dumler et al., 1989a,b). The results of the pyrolysis studies are

76 Decabromodiphenyl ether

Table 10. Thermolysis products of PBT w1th 10% decabromod1phenyl ether and 6% Sb 2 0 3~

400 °C 500 °C 600 °C 700 °C 800 °C

Bromodiphenyl ether

MBDE 10 50

D1BDE 30 100

TrBDE 100 200 50

TeBDE 500 300

PeBDE 800 400

HeBDE 1000 400

HpBDE 500 400

OBDE (500)

Bromod1benzofuran MBDF 100 300 100 50

D1BDF 500 400 200 10

TrBDF 3000 2000 400

TeBDF 4000 3000 600

PeBDF 4000 1000 200

HxBDF 1000 200

HpBDF (500)

8 From: Clausen et al. (1987); B1emek et al. (1989). Sem1quant1tat1ve values 1n mg/kg based on the sample · not confirmed. 2,3, 7 ,8·Tetrabromod1benzofuran was not found (limit of determmat1on 20 mg/kg). 2,3, 7 ,8·Tetrabromod1benzod1oxin was not found (11m1t of determmation 10 mg/kg).

given in Table 12. TeBDF were formed, with yields of up to 16%, from the 3 polymer samples. PBDF were mainly formed during pyrolysis in the presence of DeBDE and Sb20 3. At 300 °C, the conversion of DeBDE to PBDF was low, while highly brominated compounds were formed. By increasing the temperature, the yield of polybrominated compounds increased and

77 '-J cu

Table 11. Generation of 2,3,7,8-TeBDD/TeBDF by thermolysis of plast1cs w1th flame retardants as add1t1ves 1n mg/kg"•b

Compound 2,3,7,8-TeBDD 2,3, 7,8-TeBDF

Sample 400 °C 600 °C 800 °C 400 °C 600 °C 800 °C

c PBT/DeBDE/Sb2 0 3 0.02 0.01 52 5.7

PBT/DeBDE c c c 2.5 4.2 0.08

F1ve samples of ER/DeBDE mm1mum 0.05 0.3 0.01 0.4 0.6 0.01 max1mum 0.3 0.8 0.03 1.0 2.5 0.04

PR/DeBDE/Cu d 7 d d 5.7 d aFrom: Lahamat1s et al. ( 1991). bThe mg/kg values are based on the matenal used. cNon-detected, detection ilm1t 0 01 mg/kg. d = Not determmed. Table 12. Results of pyrolysis stud1es

A. Polymer Sample A: Polybutyleneterephthalate With 1 1% decabromod1phenyl ether and 5.5% antimony (Ill) ox1de (yields 1n mg/kg, relat1ve to the flame retardant) 8

300 °C 400 °C 500 °C 600 °C 700 °C 800 °C

MBDF 754 3012 5551 3513 3076

D1BDF 9 2357 10 219 15 343 8445 1547

TrBDF 9 10 747 37 911 32 751 28 592 1274

TeBDF 9 14 979 52 634 37 437 35 963 1511

PeBDF 55 2293 18 391 20 666 13 504 555

HxBDF 703 127 3713 10 438 2639 109

HpBDF 1320 246 946 491

OBDF

'I (0 co 0

Table 1 2 (continued)

B. Polymer Sample B: Polybutyleneterephthalate With 9% decabromodiphenyl ether and 7% antimony (Ill) ox1de (yields 1n mg/kg, relative to the flame retardant)

300 °C 400 °C 500 °C 600 °C 700 °C 800 °C

MBDF 13 088 7633 8510 1144

D1BDF 15 754 10 643 9721 244

TrBDF 47 456 34 408 24 842 19 276 44

TeBDF 1472 4544 48 762 35 230 23 353 367

PeBDF 5560 18 132 24 753 16 154 6988 156

HxBDF 2886 24446 18 587 8832 1633 22

HpBDF 420 6910 2877 922 100

OBDF Table 12 (continued)

C. Polymer Sample C: Polybutyleneterephthalate with 1 1% decabromod1phenyl ether and 2.7% antimony (Ill) oxide (yields 1n mg/kg, relative to the flame retardant)

300 °C 400 °C 500 °C 600 °C 700 °C 800 °C

MBDF 2202 3413 2129 610 18

DiBDF 5187 6124 1674 82

TrBDF 15 033 15 952 1738 36 15

TeBDF 17 836 17 463 901 9 12

PeBDF 9127 3349 391

HxBDF 464 2457 901 82

HpBDF 2375 1329 246 36

OBDF traces traces

Co co N

Table 12 (continued)

D. Decabromod1phenyl ether (y1elds 1n mg/kg)

300 °c 400 °c 500 °c

MBDF

D1BDF 4 8

TrBDF 4 13

TeBDF 15 11

PeBDF 16 218

HxBDF 42 109

HpBDF 1081

OBDF

8 From: Dumler et al. ( 1989b). Decabromodiphenyl ether

more lower brominated PBDF were formed. The maximum formation of PBDF occurred between 400 and 500 °C. With increasing temperature, not only ring-closure reactions but also debromination reactions with the predominant formation of tri- and tetra- brominated PBDF may occur. The same reactions probably occur at 600 °C. At these elevated temperatures, PBDD were also detected to a minor extent. The polymers with the lowest amount of Sb20 3 gave the lowest PBDF concentrations. With increasing amounts of Sb20 3, the concentration of PBDF increased, which suggests that antimony trioxide plays a catalytic role. Pure DeBOE, pyrolysed under the same conditions, produced signifi­ cantly lower PBDF concentrations than polymers with the flame retardants. In the case of pure DeBOE, the temperature for the maximum formation of PBDF shifted to 700 a c. A sample (1 g) of industrial polypropylene containing 125 g DeBDE/kg and 75 g Sb20 3/kg, and a pure DeBOE sample, without additives, were pyrolysed in a DIN-oven or in a sealed quartz ampoule at temperatures of 400, 600, or 800 °C. Combustion products obtained with the pyrolysis of pure DeBOE (50 mg) in the DIN-oven were mainly hexabromobenzenes and the yields at 400, 600, and 800 °C, were 123, 568, and 6 g/kg, respectively. PBDF/PBDD were found in concentrations of 1, 3, and 2 g/kg at 400, 600, and 800 °C, respectively. At 400 and 600 °C, HxBDF up to OBDF were found in concentrations of between 96 and 1449 mg/kg. At 800 °C, lower PBDF, e.g., TrBDF, TeBDF, and PeBDF, were also present in concentrations ranging between 11 and 35 mg/kg. The concentrations of HxBDF and HpBDF were 81 mg and 959 mg/kg, respectively, but no OBDF was found. The concentrations of PBDD at 400-600 oc for HxBDD up to OBDD were between 6 and 329 mg/kg; at 800 °C, lower brominated compounds, e.g., TrBDD, TeBDD, and PeBDD were also found at concentrations of between 8 and 35 mg/kg. HxBDD up to OBDD were present in concentrations of between 74 and 452 mg/kg. The combustion products of the samples of polypropylene containing DeBDE/Sb20 3 were mainly PBDF and PBDD and the concentrations were much higher than from the combustion of the pure DeBOE. MBDF up to HpBDF were present at concentrations of between 4762 and 107 517 mg/kg, 1033 and 49 677 mg/kg, and 353 and 29 147 mg/ kg at 400, 600, and 800 a c. respectively. At all 3 temperatures,

83 EHC 162: Brominated diphenyl ethers

TeBDF were found in the highest concentrations. The results with polypropylene containing DeBDE/Sb20 3, pyrolysed in a sealed quartz ampoule at 600 °C, showed only MBDF up to PeBDF at concentrations ranging between 8860 and 142 940 mg/kg. The highest concentrations were found for TrBDF and TeBDF. PBDD were not found. From this study, it is clear that pure DeBDE gives much lower PBDF values than polypropylene containing DeBDE/Sb20 3 (Dumler eta!., 1990). The formation of PBDD and PBDF during the pyrolysis of PBT containing DeBDE was studied at different temperatures and carrier gas compositiOns. PBDF were formed at ppm levels. Even when oxygen was available in the carrier gas, PBDD were formed at a much lower level than PBDF. In the presence of 10% oxygen, the maximum yield of tetra- to octabromodibenzofurans was 70 ppm at 600 oc. The yields of 2,3,7,8-TeBDF and 1,2,3, 7 ,8-PeBDF were less than 4.5 ppm. The thermal degradation processes of the polymer were investigated using thermogravimetric analysis. The flame retardant did not exert any influence on the elementary chemical degradation processes. The flame retardant activity of DeBDE consists of the emission of brominated species in the gas phase, which scavenge the propagation radicals and reduce flammability. The mechanisms of formation of PBDD and PBDF from DeBDE in PBT consist of a combination of a condensed phase and a gas phase mechanism (Luijk & Govers, 1992). Macro-pyrolysis experiments were performed in a quartz tube reactor. The polymer sample, PBT, was inserted in the pre-heated tube and exposed at 400-700 oc for 20 min. The carrier gas was nitrogen, or nitrogen combined with 5% or 10% oxygen. The results are given in Tables 13 and 14. PBDF were formed in all tests with the different carrier gases, but the yield of PBDD was at least two orders of magnitude lower tha.1 that of the PBDF. In a nitrogen atmosphere, no PBDD were detected (Luijk & Govers, 1992). Using GC/MS, Sovocool et a!. (1990) analysed pyrolysates of PBT resins (tlame retarded with DeBDE) which had been exposed to temperatures of 400 and 600 oc in the presence of oxygen. They found brominated dioxins, brominated dibenzofurans, brominated naphthalenes, brominated benzenes and brominated

84 Table 13. The y1eld of PBDF dunng the pyrolysis of PBT/DeBDE in ppm relative to blend, under different earner gas conditions8

Temper- TrBDF TeBDF 2,3,7,8- PeBDF 1 ,2,3,7,8- HxBDF HpBDF NBDF ature [°C] TeBDF PeBDF

N1trogen

400 6.7 (0.8) 3.9 (2.4) 0.15 (0.09) 8.7 (0.5) 0.2 (NS)b 10.6 (1.9) 3.7 (0.4) 0.05 (0.00)

500 15.9 (2.8) 14.5 (0.8) 0.6 (0.1) 13.3 (2.5) 0.1 (NS)b 9.8 (1 .1) 4.8 (0.9) 0.1 (0.1)

600 6.8 (0.4) 4.9 (0.2) 0.2 (0.0) 4.5 (1.8) 0.1 (NS)b 2.9 (0.5) 0.7 (0.2) NDC

700 4.2 (0.8) 1.2 (0.1) 0.1 (NS) 0.5 (0.0) (NS)b 0.2 (0.0) 0.06 (0.02) NDC

Nitrogen + 5% oxygen

400 4.7 (1 .4) 3.6 (1. 1) 0.2 (0.1) 3.6 (1 .1) 0.1 (NS)b 2.9 (1 .2) 0.7 (0.3) NDC

500 7.7 (0.7) 6.4 (0.4) 0.4 (0.1) 5.3 (0.1) 0.1 (0.0) 5.3 (0.1) 1.1 (0.0) NDC

600 22.1 (2.7) 17.2 (1 .8) 2.4 (0.3) 17.7 (3.2) 0.8 (0.2) 16.8 (1 .3) 4.8 (0.3) 0.3 (0.0)

700 15.7 (0.3) 7.6 (0.1) 1.2 (0.0) 6.6 (1.2) 0.4 (0.1) 5.7 (0.2) 1.3 (0.3) 0.08 (0.03)

Nitrogen + 1 0% oxygen

400 9.6 (0.7) 7.5 (1.0) 0.3 (0.1) 7.7 (1 .5) (NS)b 5.9 (3.0) 1.8 (1.0) NDC

500 11.0 (0.3) 8.7 (0.5) 0.6 (0.1) 8.8 (0.4) 0.2 (0.0) 8.7 (0.8) 3.7 (0.3) NDC

600 28.8 (3.2) 20.8 (1.8) 3.4 (0.5) 21 .6 (3.4) 1.2 (0.2) 17.8 (1 .3) 7.6 (1 .1) 0.8 (0.1)

700 17.5 (0.7) 10.3 (1 .4) 2.0 (0.2) 8.9 (0.3) 0.6 (0.0) 5.3 (0.3) 2.1 (0.3) 0.02 (0.02)

Q) 8 From: Luijk & Govers (1992). 01 bNS = not separable, due to interferences. eND = not detected (below detection limit). Q:) 0')

Table 14. The y1eld of PBDD dunng the pyrolysis of PBT/DeBDE 1n ppb relative to blend, under different earner gas condltlonsa

Temperature TrBDD TeBDD 2,3,7,8- PeBDD 1 ,2,3,7,8- HxBDD HpBDD NBDD )OC) TeBDD PeBDD

N1trogen + 5% oxygen

400 NSb NSb NSb NSb Nsb ND0 ND0 ND0

500 NSb NSb NSb NSb Nsh NSb 7 (2) 4 (4)

600 NSb 8 (NSb) NSb 44 (6) Nsb 110 (10) 43 (0) 13 (1)

700 NSb 5 (1) NSb 19 (6) Nsb 40 (5) 8 (2) ND0

Nitrogen + 10% oxygen

400 NSb NSb NSb NSb Nsh ND0 ND0 ND0

500 6 (NSb) NSb NSb 3 (NSb) Nsb 48 (NSb) 16 (NSb) ND0

600 44 (NSb) 29 (7) NSb 75 (NSb) NSb 106 (11) 46 (4) 16 (0)

700 32 (18) 24 (NSb) NSb 21 (NSb) Nsb 19 (3) 4 (4) ND0

8 From: LuJjk & Govers (1992). bNS ; Not separable, due to Interferences. 0 ND ; Not detected (below detectiOn limit). Decabromodiphenyl ether

toluenes, brominated biphenyls, and brominated methyldibenzo­ furans (Me-PBDF). Besides the methyldibenzofurans, other (C2 and C3) alkyl-PBDF were found in the pyrolysates. Numerous congeners of ethyl- (and/or dimethyl)-PBDF and a few propyl (and/or trimethyl or ethylmethyl)-PBDF were detected. The C2- and C3-alkyl-PBDF found in the pyrolysates exhibited relatively intense (M-CH3)+ fragments, supporting the argument for ethyl-and propyl or ethyl-methyl substitutions rather than dimethyl and trimethyl substitution patterns. Early in 1987, the General Electric Company (GE) began to investigate the pyrolysis of polybutyleneterephthalate (PBT) flame retardant systems. The initial work was carried out at temperatures of 600-900 °C, but subsequent efforts were at processing temperatures in the range of 200-500 oc. The results showed little or no formation of PBDD at temperatures of 250-400 oc; concentrations of PBDF in the pyrolysed products were as high as about 6000 mg/kg. The concentrations of 2,3,7 ,8-substituted dibenzofurans were much lower, not exceeding a maximum of 150 mg/kg. The results for PBDD and PBDF were much higher than would be expected, based on the previous work by Buser and Hutzinger. The results were also inconsistent with what was observed in combustion experiments. The explanation was that the exposure times and conditions used did not represent a good model of what would actually occur in moulding equipment (BFRIP, 1990). In the GE experiments at the Fresenius Institute, an apparatus was used in which a small sample of the polymer in the form of a finely ground powder was exposed to the pyrolysis temperature in a flowing air stream. The pyrolysis time for these samples varied from lO min at the high temperatures to as much as 1.5 h at the low temperatures. This is in contrast to extrusion and moulding operations in which the polymer is in the form of a molten mass, air is largely excluded, and exposure lasts less than 1 min. Dumler et al. ( 1989b) have recently pub I ished data from studies on the pyrolysis of PBT/DeBDE resins. This work was conducted in apparatus identical to that used by GE, thus, the results can be compared. In the report by Hutzinger and co­ workers, concentrations of PBDF were calculated relative to the flame retardant only. Recalculation of the results by BFRIP

87 EHC 162: Brominated diphenyl ethers

(1990), on the basis of the total polymer, showed general agreement with the GE results (fable 15). Hutzinger's recent work was summarized in a report by Pohle of the Umwelbundesamt (Umweltbundesamt, 1989). In this work, the tube furnace (DIN Apparatus) and the vertical quartz oven (VCI Apparatus; as used by the Fresenius Institute) were used to pyrolyse polymers containing PBDE at temperatures ranging from 600 to 750 °C. The results showed that PBDF were formed under these conditions, but that 2,3,7,8-TeBDF was only a small fraction of the total. In general, the results were similar to those reported earlier by Hutzinger and GE. Because of the lack of good data collected under actual operating conditions, BFRIP met with 6 major polymer producers in 1988, to design a series of experiments to investigate the behaviour of DeBDE and OBDE in HIPS, ABS, and PBT under controlled moulding or extrusion conditions. The experiments are outlined in Tables 16 and 25 (in OBDE section 4.2.3). For the three polymer systems, HIPS/DeBDE, ABS/OBDE, and PBT/ DeBDE, samples were moulded in the application laboratories of polymer producers. For the moulding operations, the severity of operations ranged from normal to extreme. Normal conditions were those in the middle range recommended by the resin manufacturers for processing. The abusive conditions were at, or slightly above, the maximum recommended exposure time and temperature. The extreme conditions were well above those recommended by the resin manufacturer and resulted in samples with severely degraded physical properties and/or colour. After moulding, all the samples were analysed by Triangle Laboratories, Research Triangle Park, NC (fLI). Samples were also sent to the US EPA Laboratory in Las Vegas for confirming analyses. The results of these analyses ?~e summarized in Tables 17 and 26 (in OBDE section 4.2.3) and are discussed more fully in the report of this study made at Dioxin'90 (McAllister et al., 1990; BFRIP, 1990). With the exception of a single sample, PBDD were not identified in any of the samples and 2,3, 7,8- TeBDF were seen only in this one sample at very low concentrations. In general, the Triangle Park and US EPA results agreed fairly well for the TBDF and TBDD.

88 Table 15. Comparison of GE and Hutzinger results on pyrolysis of PBT/DeBDE Resin (PBT/11% DeBDE/2. 7% antimony trooxide) All concentrations 1n mg/kg relative to total polymer"

300 °C 400 °C 500 °C 600 °C 700 °C BOO °C

Compound General Dumler General Dumler General Dumler General Dumler General Dumler General Dumler Electric et al. Electric et al. Electric et al. Electric et al. Elect roc et al Electric et al. USA (1989) USA (1989) USA (1989) USA (1989) USA (1989) USA (1989)

MBDF NAb 240 370 230 70 NDC

DiBDF 570 673 180 9

TrBDF 1650 1750 190 36 NDC

TeBDF 5200 2000 1960 1200 1920 490 100 24 4 0.03 NAb

2,3,7,8- 150 64 120 19 0.4 0.005 TeBDF

PeBDF 5900 1200 1003 1300 370 350 40 8 0.006

1 ,2,3.7 ,8- NDC NDC NDC NDC NDC NDC PeBDF

HpBDF NDC 260 NDC 150 50 40 3 4 0.1 NDC

OBDF Tr Tr NDC NDC

Total 13 450 310 4100 3383 3220 2430 943 234 35 4 0.04 NAb TeBDF- HpBDF

8 From: BFRIP (1990). O:l bNA = not analysed. (0 eND = not detected. EHC 162: Brominated diphenyl ethers

Table 16. Mould1ng studies With two polymer/FR systems at different processing temperatures"

Polymer/FRb Seventy Cond1t1ons

HIPS/DeBDE None Base res1n, not moulded Normal 215-220 °C, 30- second cycle Abusive 235-245 °C, 5-min cycle Extreme 265-270 °C, 7-min cycle

PBT/DeBDE Normal 255 °C, 23-second cycle Abusive 255 °C, 5-min cycle Extreme 255 °C, 10-mln cycle

8 From: McAllister et al. (1990). b HIPS/DeBDE High Impact polystyrene/ 84.3% DeBOE + 12.0% ant1mony tnox1de 3.7% PBT /DeBOE Polybutyleneterepthalate/ 88.0% DeBOE + 6.5% antimony tnoxide 5.5%

Different interpretations of the analytical results of the 2 laboratories resulted in larger differences in values for hexa­ through octa-brominated furans. These data showed that the processing of the resin systems under normal conditions did not change the composition compared with that of the base resin formulation. Even under abusive conditions, there was little generation of PBDF or PBDD. In fact, PBDD were observed in only 2 of the samples under abusive or extreme exposures. 2,3, 7 ,8-Substituted dibenzofurans were not observed, except in one sample in which very low ppb levels were seen (Tables 17 and 26 in OBDE section 4.2.3).

90 Table 17. Companson of Tnangle Laboratones Inc. (TLI) (Research Tnangle Park) and US EPA Laboratory (las Vegas) results on moulded polymer samples conta1mng vanous flame retardants. (All concentrations are m mg/kg)8

H1gh 1mpact polystyrene with decabromod1phenyl ether

Base resm 1 222-1 6-0 Normal 1 222-1 6-1 Abus1ve 1 222-16-2 Extreme 1222-16-3

Compound TLI US EPA TLI us EPAC TLI US EPAd TLI EPA

Total TBDF 0.01 ND 0.01 0.01 0.002 0.02 ND

PeBDF 0.04 0.004 0.05 0.06 0.02 0.2 0.009

HxBDF < 5.3 0.95 < 14.3 < 5.5 0.11 < 34.1 0.2

HpBDFb < 0.6 0.72 < 3.5 < 2.1 0.08 < 10.6 2.1

PBDFb < 4.1 0.15 < 9.3 < 7.0 ND < 35.7 3.2

(D (0 f\J

Table 17 (continued)

PBT with decabromod1phenyl ether

Base resin Normal 1 222-1 6-6 Abus1ve 1222-16-7 Extreme 1 222-1 6-8

Compound TLI US EPA TLI US EPAd TLI US EPA TLI US EPAe

Total TeBDD < 0.001 < 0.0002 < 0.002 0.001

Total PeBDD < 0.001 < 0.0002 < 0.013 0.006

Total TeBDF 0.003 0.003 0.007 0.03 0.2 1.0

Total PeBDF 0.02 0.002 0.09 > 7.8 > 25 >54

Total HxBDF 0.11 0.013 1.1 > 16.1 > 120 > 7.0

Total HpBDFb 0.31 < 4.3 3.0 < 4.6 58.5 < 12.1

Total OBDFb 0.95 < 16.9 3.2 < 9.9 7.5 < 68.8 8 From: BFRIP (1 990). Values preceeded by < are max1mum possible. Analytical s1gnals met ident1f1cat10n critena, but may include contribution from interferences. US EPA and TLI used different identification criteria, resulting in differences in reported values. bconcentrat1ons of HpBDF and OBDF from TLI are not validated because of lack of standards. Concentrations are reported for comparison only. csample 1 222-1 6-1 was spilled during workup. d Average of 2 analyses of same sample. eus EPA results not validated. Decabromodiphenyl ether

4.3.3.2 Workplace exposure studies

The occurrence of PBDF and PBDD during the thermal processing of glass-filled PBT resin containing DeBDE at 70 g/kg and Sb20 3 at 62 g/kg or no flame retardant was studied. No PBDD (limit of determination 2 ng) were found. PBDF were present and isomers containing bromine at the 2,3,7,8-position represented less than 10% of the total PBDF. Fumes evolved during thermal processing of the resins were collected at the die­ head during extrusion. The temperature in the 4 temperature zones was between 216 and 250 °C. It was found that thermal processing of resin with DeBDE/Sb20 3 yielded higher concentrations of PBDF in the fumes than that of resin without the flame retardants. The concentrations found in two samples of resin with flame retardant and one sample without flame retardant are given in Table 18. In addition to these pyrolysis and moulding experiments, studies have been performed to determine the possibility of the workplace exposure to PBDF and PBDD of workers in extrusion or moulding facilities. The first of these studies was a simulation sponsored by General Electric (GE) at Battelle Laboratories in Columbus, OH (BFRIP, 1990). For this work, an experimental extrusion apparatus was used in which the total volatiles from the extruder could be collected and analysed. A typical commercial PBT/DeBDE resin was extruded, the volatiles were collected and analysed at the Fresenius Institute. The results of the analysis were used to estimate a probable workplace concentration of 0.76 ng/m3 as TCDD equivalents. The following experiment was carried out to determine the risks to employees working in the actual production of PBT resin, flame retarded with DeBDE, at Hoechst Celanese facility at Bishop, Texas (Hoechst Celanese Corp., 1988). High-volume samples were taken above the extruder die-head, the extruder vent port, the fibreglass addition port, and the raw material feeder, because these were the areas where off-gassing was most likely to occur and where employees could be exposed to the off-gases from extrusion. Source samples can be considered as worst-case situations, as samplers were placed directly in the off-gas streams.

93 EHC 162: Brominated diphenyl ethers

Table 18. Concentrations of PBOF in resms 1n ng per sample component8

Substance Two samples w1th flame retardant One sample without flame retardant

TeBOF 201 1310 76

2,3,7 ,8-TeBOF 15 114 6

PeBOF 131 820 43

1,2,3,7,8- NO(< 2) NO(< 5) NO(< 2) PeBOF

HxBOF 80 425 23

1,2,3,4, 7,8- < 6 49 2 HxBOF

HpBOF < 11 51 2

Total PBOF 423 2606 144

8 From: (V1nc1 & Craig, 1988). The values are the total quantity of PBOF (In ng) found in the 2 sample components, wh1le the values of the specif1c isomers are given as values present in the total PBOF. For example: 15 ng of 2,3,7,8-TeBDF present in 201 ng total PBOF. No PBOO was detected in any of these samples (limit of determination, 2 ng). bNO = not detected.

A fifth sample was taken in an unused guard house, 90 m from the extruder building, as a field control. Full-shift personal samples were taken on all operators and helpers on each shift to determine the actual employee exposure. Each sampler was worn by employees for the entire 24-h period. The operating temperature was 240-260 °C. Personal samples are regarded as more representative than the area/source samples, since they were worn by employees during the production run.

94 Decabromodiphenyl ether

The concentrations (expressed as TCDD equivalents) in ng/m3 in the different air samples were:

Fibreglass port 0.027 Extruder die-head 3.589 Extruder vent port 0.191 Raw material feeder 0.015 Guard house 0.0004 Personal (three) samples 0.019, 0.011, 0.122.

BFRIP sponsored a study at a commercial PBT extrusion facility in 1988. This study was designed and conducted with input from the National Institute of Occupational Safety and Health (NIOSH) and the US EPA. In this study, both area samples and personnel monitors were used to collect information on potential exposures. Area samples were collected from locations expected to show maximum levels of volatile components. Personnel samples were collected with pumps worn by workers, and represented the average levels to which workers were exposed. In all cases, exposures were calculated in terms of TeCDD equivalents, using the concept of "Toxicity Equivalent Factors" (TEF) (the concentration of a particular chlorinated (brominated) dibenzo­ dioxin or dibenzofuran is converted to an equivalent concentration of 2,3,7,8-TeCDD by multiplying by the appropriate factor). It should be noted that this conversion of exposure values for PBDF to TeCDD toxicity equivalents is only an estimate and is by no means generally accepted. The results from the area samples are summarized in Table 19 and from personnel samples in Table 20. The maximum worker exposure for PBDF was 0.1 ng/m3 , expressed as TeCDD toxicity equivalents (BFR/CEM Working Group, 1989; BFRIP, 1990; EBFRIP, 1990). Determination of the occupational exposure during extrusion of PBT containing DeBDE at 90 g/kg and antimony trioxide at 80 mg/kg, was carried out by BASF, in Germany. In air, the total PBDF concentration close to the extruder head was 72.9 JJ.g/m3 3 and that in the rooms ranged from 0.169-0.989 JJ.g/m . Concen­ trations of hexabromo- and heptabromodibenzofurans were the highest, followed by penta- and octabromodibenzofuran. The total 3 PBDD concentration in the room was 28.12 ng/m , being mainly

95 (j:) Table 19. Results from BFRIP air sampling tests• 0) Compound Toxic1ty Area Samples equ1valent F1breglass port Extruder d1e head Extruder vent port Feed hopper Guard gate factor CO NCb TCDD CO NCb TCDD CO NCb TCDD CO NCb TCDD CO NCb TCDD equiv- equiv- equiv- equiv- equiv- alentc alentc alentc alentc alentc 2,3,7,8-TeBDD 1.00000 0.0001 0.0001 0.0033 0.0033 0.0016 0.0016 0.0000 0.0000 0.0001 0.0001 1 ,2,3,7 ,8-PeBDD 0.50000 0.0001 0.0000 0.0059 0.0030 0.003 0.0016 0.0006 0.0003 0.0001 0.0001 1 ,2,3,4,7 ,8·HxBDD 0.10000 0.0002 0.0000 0.6220 0.0622 0.202 0.0202 0.0002 0.0000 0.0006 0.0001 1 ,2,3,6,7 ,8-HxBDD 0.10000 0.0002 0.0000 0.6221 0.0622 0.202 0.0202 0.0002 0.0000 0.0006 0.0001 OBDD 0.00100 0.0006 0.0000 0.0382 0.0000 0.020 0.0000 0.0009 0.0000 0.0023 0.0000

2,3,7,8-TeBDF 0.10000 0.0118 0.0012 0.0017 0.0002 0.104 0.0104 0.0055 0.0005 0.0001 0.0000 1,2,3,7,8-PeBDF 0.05000 0.0154 0.0008 0.0072 0.0004 0.005 0.0002 0.0092 0.0005 0.0002 0.0000 1 ,2,3,4,7 ,8-HxBDF 0.10000 1.0770 0.1077 126.8512 12.6851 1.962 0.1962 0.6036 0.0604 0.0006 0.0001 Total TeBDD 0.00000 0.0356 0.0000 1.9360 0.0000 2.199 0.0000 0.0412 0.0000 0.0001 0.0000

Total PeBDD 0.00000 0.0067 0.0000 0.3079 0.0000 0.003 0.0000 0.0048 0.0000 0.0001 0.0000 Total HxBDD 0.00000 0.0073 0.0000 36.9172 0.0000 0.448 0.0000 0.0084 0.0000 0.0006 0.0000

Total TeBDF 0.00000 3.4764 0.0000 394.2480 0.0000 13.735 0.0000 1.4432 0.0000 0.0620 0.0000 Total PeDBF 0.00000 7.4 785 0.0000 1412.8761 0.0000 55.384 0.0000 3.5971 0.0000 0.0000 0.0000 Total HxBDF 0.00000 2.6888 0.0000 4544.6098 0.0000 146.321 0.0000 0.5275 0.0000 0.0000 0.0000

A1r concentration 0.1098 12 8163 0.2503 0.0618 0.0004 ng/m3

8 From: EBFRIP (1 990). 3 bAll concentrations are expressed as ng/m • cToxic1ty equivalent factors are the 1nternat1onal values adopted by the US EPA 1n 1989. Table 20. Results from BFRIP air sampling tests• Compound Toxicity Personnel monitors equivalent 6559 12524 49834 factor CO NCb TCDD CO NCb TCDD CO NCb TCDD equivalentc equivalentc equivalentc

2,3,7,8-TeBDD 1 00000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 1 ,2,3, 7 ,8·PeBDD 0.50000 0.0000 0.0000 0.0005 0.0002 0.0000 0.0000 1 ,2,3,4,7,8-HxBDD 0.10000 0.0000 0.0000 0.0025 0.0002 0.0000 0.0000 1 ,2,3,6,7 ,8-HxBDD 0.10000 0.0000 0.0000 0.0025 0.0002 0.0000 0.0000 OBDD 0.00100 0.0000 0.0000 0.0093 0.0000 0.0000 0.0000

2,3,7,8-TeBDF 0.10000 0.0132 0.0013 0.0000 0.0000 0.0000 0.0000 1 ,2,3,7 ,8·PeBDF 0.05000 0.0365 0.0018 0.0012 0.0001 0.1855 0.0093 1 ,2,3,4, 7 ,8-HxBDF 0.10000 0.3543 0.0354 0.1405 0.0140 5.4102 0.5410

Total TeBDD 0.00000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Total PeBDD 0.00000 0.0000 0.0000 0.0005 0.0000 0.0000 0.0000 Total HxBDD 0.00000 0.0000 0.0000 0.0025 0.0000 0.0000 0.0000

Total TeBDF 0.00000 1.4065 0.0000 1.1929 0.0000 7.6914 0.0000 Total PeDBF 0.00000 5.0801 0.0000 5.9643 0.0000 38.8162 0.0000 Total HxBDF 0.00000 6.5995 0.0000 61.9528 0.0000 70.1965 0.0000

Air concentration 0.0386 0.0149 0.5503 ng/m3

aFrom: EBFRIP (1990). 3 bAll concentrations are expressed as ng/m . (() cT ox1city equivalent factors are the international values adopted by the US EPA 1n 1989. '-.1 EHC 162: Brominated diphenyl ethers

octa- and hexabromodibenzodioxins. The tetrabromodibenzodioxin concentration was 2.04 ng/m3 (Kraus, 1990). Umweltbundesamt (1989) reported the results from the workplace study conducted by BASF in a PBT extrusion facility. The results from the BASF study are summarized in Table 21. The higher level observed in the vicinity of the extruder head was removed from the workplace by local ventilation. According to the BASF report, workers spent most of their time in the "Production room" or at the "Bagging station". Only if there were problems with the equipment did they work near the extruder. The actual worker exposure would be approximately the levels observed in the production room or at the bagging station. The results of the BASF and BFRIP studies are summarized in Table 22. With the exception of the BASF sample collected at the extruder head, the results are generally consistent between the two studies. The higher value for this sample, compared with that from the extruder die-head from the BFRIP, could be a result of a difference in the placement of the sampler (BFRIP, 1990). An occupational exposure limit has not been established for any PBDD or PBDF, but a recent paper by Leung et a!. (1988) provides guidance. Applying a 100-fold safety factor to the no­ observed-effect level in animal studies, an occupational exposure limit of 0.2 ng/m3 is obtained. For other compounds that behave similarly to TeCDD in animals tests, safety factors from 2 to 10 have been used to establish the occupational exposure limit. Using a safety factor of 10, the occupational exposure limit for TeCDD 3 becomes 2 ng/m . With the exception of the two samples from the extruder die-heads, all of the values from the BASF and BFRIP 3 studies were below 2 ng/m . The studies also indicate that workers are unlikely to be routinely exposed to levels higher than 3 0.2 ng/m . BASF has submitted to the US EPA a report of the biological monitoring of 5 workers, who were employed in the extrusion of PBT containing DeBDE as a flame retardant (BFRIP, 1990). The results indicated blood concentrations of 2,3,7,8-TeBDF and 2,3,7,8-TeBDD of 100-500 ngllitre. All workers appeared in good health. The finding of 2,3,7,8-TeBDD in the workers was particularly surprising, since air samples had not revealed the

98 Table 21. Results from BASF a1r sampling tests

Compound Tox1c1ty Extruder equ1valent factor Production room Work station Bagg1ng station Extruder head

CO NCb TCDD CO NCb TCDD CO NCb TCDD CO NCb TCDD equivalentc eqUivalentc equ1valentc equivalentc

2,3,7 ,8-TeBDD 1.00000 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0 0.0000

1,2,3,7,8-PeBDD 0.50000 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0 0.0000

1,2,3.4,7 ,8-HxBDD 0.10000 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0 0.0000

1,2,3,6, 7 ,8-HxBDD 0.10000 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0 0.0000

OBDD 0.00100 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0 0.0000

2,3,7,8 TeBDF 0.10000 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0000

1 ,2 ,3, 7 ,8-PeBDF 0.05000 0.0 0.0000 1.3 0.0650 0.0 0.0000 87.0 4.3500

1,2,3,4,7,8-HxBDF 0.10000 0.0 0.0000 2.6 0.2600 0.3 0.0300 1186.0 118.6000

Total TeBDD 0.00000 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0 0.0000

Total PeBDD 0.00000 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0 0.0000

(0 (0 -0 0

Table 21 (continued)

Total HxBDD 0.00000 0.0 0.0000 0.0 0.0000 0.0 0.0000 0.0 0.0000

Total DiBDF 0.00000 1.1 0.0000 1.3 0.0000 0.2 0.0000 322.0 0.0000

Total TnBDF 0.00000 13.0 0.0000 7.4 0.0000 1.1 0.0000 705.0 0.0000

Total TeBDF 0.00000 20.0 0.0000 33.7 0.0000 5.1 0.0000 9BO.O 0.0000

Total PeBDF 0.00000 9B.O 0.0000 7143.0 0.0000 B.6 0.0000 3910.0 0.0000

Total HxBDF 0.00000 594.0 0.0000 554.0 0.0000 13.0 0.0000 22 162.0 0.0000

Total HpBDF 0.00000 260.0 0.0000 200.0 0.0000 BB.O 0.0000 39 550.0 0.0000

Total OBDF 0.00100 0.0 0.0000 0.0 0.0000 7.0 0.0070 5275.0 5.2750

A1r concentration 0.0000 0.3250 0.0370 126.2250 ng/m3

•From: EBFRIP (1990). 3 bAll concentrations are expressed as ng/m . cT OXICity equivalent factors are the international values adopted by the US EPA in 19B9. Decabromodiphenyl ether

Table 22. Summary of BASF and BFRIP air sampling tests"

Location Study Concentration (ng/m3 air) TCDD equivalent

Personnel-1 BFRIP 0.039

Personnel-2 BFRIP 0.015

Personnel-3 BFRIP 0.550

Room air BASF 0.000

Work station BASF 0.325

Baggmg station BASF 0.037

Extruder head BASF 128.225

Fibre glass addition port BFRIP 0.110

Extruder die head BFRIP 12.816

Extruder vent port BFRIP 0.250

Feed hopper BFRIP 0.062

Guard gate BFRIP 0.000

8 From: EBFRIP (1990).

presence of brominated dioxins. These findings have not yet been confirmed, but a follow-up study is in progress. Investigations by plastic producers have shown that PBDF and PBDD can be formed, not only on combustion of plastics containing PBDE, but also during the blending of the flame retardant into a polymer. This has been substantiated by BASF, who measured the workplace atmosphere around extruders.

4.4 Ultimate fate following use

4.4. 1 General

For the ultimate fate of DeBDE following use, and its effects on the environment, see section 6.1. of the General Introduction.

101 EHC 162: Brominated diphenyl ethers

4.4. 2 Exposure of the general population

No data are available concerning the direct exposure of the general population to DeBDE. In a study by Ranken et al. (1990) to investigate the possibility of exposure to PBDD/PBDF from TV sets, three new TV sets were placed in an 8.81 m3 test chamber. Sets A and B were purchased locally, while set C was provided by the manufacturer. The rear portion of each television set cabinet was constructed from polystyrene. The purchased televisions were flame retarded with 11.5% DeBDE. Set C was made of high­

impact polystyrene, flame retarded with DeBDE/Sb20 3 • In order to determine background levels of PBDD/PBDF, air was pulled through the empty chamber and through a sampler for 8 h/day, for 3 days. Two purchased sets were placed in the chamber. Air was pulled through the chamber for 8 h/day, for 3 days. The experiment was repeated for another 3 days. The television set (C) was placed in the room for 3 days, but the television was not in operation. In all the described experiments, no PBDD/PBDF were found. Finally, the air was monitored for 24 h while the television set C was operating. No PBDD/PBDF were found. On the basis of the limits of determination, PBDD/PBDF emissions from the operating television sets can be calculated to be less than 0.17-1.52 3 pg TeBDD/m , 0.35-0.39 pg PeBDD/m3, 0.09-0.33 pg 3 TeBDF/m , and 0.14-0.19 pg PeBDF/m3 of air. The authors concluded that, in actual practice, these values would be lower by a factor of 10-100 because of the dilution effect of a normal room size and the expected air turnover.

4.5 Fire accident

Bruckmann et al. (1989) reported about an accidental fire in a stock-house in which, according to an inventory file, 2.5 tonnes of flame retardants (a mixture of DeBDE and antimony trioxide (Traflam PO 80)) was stored. Four wipe samples and 6 solid samples of partly burnt material were taken several hours after the fire. At the time of sampling, it was discovered that only a minor quantity of the bags with the flame retardant had been in contact with the fire. The 4 wipe samples contained tetra-, penta-, hexa-, hepta-, and octabromodi-benzofurans in the following

102 Decabromodiphenyl ether

concentrations; 4.0-123, 0.82-77.6, 4.5-51.7, 0.25-12.8, and 0.53-8.5 ng/m2. PBDD were not found (limit of determination 1 ng/m2 per isomer). The PBDF contents of the solid samples were low with the highest concentration at 1 J.Lg/kg.

4.6 Simulated fire conditions

In the experiments conducted by the BFRIP, samples of high­ impact polystyrene (HIPS) and HIPS/DeBDE/Sb20 3 were burned in a Mass Burning Rate Apparatus with 21% oxygen to simulate a real fire scenario. The temperatures ranged from 500 to 800 °C. Soot and char were collected and analysed for PBDD and PBDF (Table 23).

Table 23. Analytical results from combustion products of HIPS/DeBDE6

Compound Concentration

Char Soot (mg/kg) (mg/kg)

Brominated dibenzod1oxins NDb NDb

Brommated d1benzofurans:

MBDF 0.64 556

D1BDF 0.54 641

TrBDF 0.23 352

TeBDF < 0.1 73

2,3, 7 ,8-TeBDF < 0.1 1.8

PeBDF < 0.1 3.5

HxBDF-OBDF < 0.1 < 0.1

8 From: McAllister et al. (1990); Pmkerton et al. (1989). bND = Not detected. A smgle study on a mixed range of PBDE, between HxBDE and DeBDE, indicated little bioconcentratiOn 1n carp With a bioconcentration factor of < 4 after 8 weeks of exposure (CBC, 1982).

103 EHC 162: Brominated diphenyl ethers

No PBDD or PBDF were found in the HIPS without flame retardant. Low levels of bromodibenzofurans were found in the char of the flame-retarded HIPS, however, the levels of brominated furans ranged from 3.5 mg penta- to 641 mg dibromodibenzofurans/kg. No PBDD were found in char and soot. A maximum of 1.8 mg/kg of 2,3,7,8-TeBDF was present in soot (Pinkerton et al., 1989; McAllister et al., 1990).

4. 7 Bioaccumulation

A bioconcentration study was carried out with rainbow trout under static conditions. The concentration in the water was 20 p,g 14C-DeBDE/Iitre. Fish were exposed for 0, 112, 1, 2, 4, 6, 12, 24, or 48 h. There was no measurable accumulation of DeBDE in flesh, skin, or viscera (Brosier et al., 1972; Norris et al., 1973, 1974, 197Sa). A single study on mixed PBDE between HxBDE and DeBDE indicated little bioconcentration in carp with a bioconcentration factor of < 4 after 8 weeks of exposure (CBC, 1982).

104 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

5.1 Environmental levels

5.1.1 Air

Decabromodiphenyl ether was identified in 10 samples of air collected in the vicinity of two manufacturing facilities in 3 concentrations ranging from 0.016 to 25 11-g/m . The compound was present in air in the form of particulates (Zweidinger et al., 1977).

5.1.2 Water

DeBDE was determined in 15 water samples collected in Japan in 1977. DeBDE was not present in any of the samples (limit of determination 0.2-2.5 11-g/litre) (Environment Agency Japan, 1983). DeBDE was not detected in 75 water samples (limit of determination 0.1 11-g/litre) in 1987 and was not detected in 141 samples collected at 47 locations (limit of determination 0.06 11-g/litre) in 1988-89 in Japan (Environment Agency Japan, 1989, 1991). Yamamoto et al. (1991) analysed water from the Kino River basin for the presence of DeBDE. In 12 samples of river water, the concentrations of DeBDE were all below 0.1 11-g/litre water.

5. 1.3 Aquatic sediments

DeBDE was determined in 15 sediment samples collected in Japan in 1977. DeB DE was not found in any of the samples (limit of determination 25-870 11-g/kg dry weight) (Environment Agency Japan, 1983). Marine, estuarine, and river sediment samples were collected at different places in Japan in the years 1981-83 and analysed for DeBDE. The DeBDE occurred in 6 river and 1 estuarine sediment sample (7 out of 15 samples) in the range of 20-375 11-g/kg, during this period (Watanabe et al., 1987b).

105 EHC 162: Brominated diphenyl ethers

DeBDE was identified at 20 p.g/kg (dry weight) in one sample of 3 estuarine sediment samples from Osaka but was not detected in samples from Tokyo, Matsuyama, or Hiroshima (Watanabe et al., 1987b). In 1987, an environmental survey was conducted concerning DeBDE in sediment in Japan. DeBDE was detected in 16 out of 60 samples at concentrations ranging from 10 to 1370 p.g/kg (limit of determination 7 p.g/kg dry weight) in 1987 and was detected in 39 out of 129 samples collected at 43 locations at concentrations ranging from 4 to 6000 p.g/kg (limit of determination 4 p.g/kg dry weight) in 1988-89 (Environment Agency Japan, 1989, 1991). A sample was collected using a dredger, from the upper sediment layer of the Second Neya River in Osaka, Japan, in 1983. The sample contained approximately 0.2 mg DeBDE/kg dry weight (Watanabe et al. (1986). Yamamoto et al. (1991) analysed 20 sediment samples collected from the Kino River in Japan and found that DeBDE was present in all the samples. The concentrations ranged from 0.003 to 11.6 mg/kg dry weight. Zweidinger et al. (1978) found DeBDE at levels ranging from not detectable to 1 g/kg in sediment samples in the vicinity of a flame retardant manufacturing facility in the USA. DeBDE (limit of determination < 10 p.g/kg) was found in sediment in the vicinity of bromine facilities in El Dorado and Magnolia, Arkansas (DeCarlo, 1979) and also in sludge samples from a discharge-treatment zone of a DeBDE facility in Bayonne, New Jersey (US EPA, 1988; IARC, 1990).

5. 1.4 Aquatic and terrestrial organisms

One of 3 mussel samples, collected in 1981-85, from Osaka Bay, Japan, contained 1.4 p.g DeBDE/kg (wet weight basis) (Watanabe, 1987; Watanabe et al., 1987a,b). DeBDE was not found in mullet, go by, sea bass, horse mackerel, sardine, mackerel, or hairtail from this area or in mussel, mullet, goby, sardine, mackerel, or hairtail from other locations (limit of determination < 0.5 p.g/kg). A total of 17 samples were analysed.

106 Decabromodiphenyl ether

In 1987, an environmental survey was conducted concerning DeBDE in fish. It was not detected in 75 fish samples in 1987 and was not detected in 138 fish samples collected at 46 locations in 1988-89 (limit of determination 5 llg/kg wet weight) (Environment Agency Japan, 1989, 1991).

5.2 Exposure of humans

5. 2. 1 Occurrence of DeBOE in human tissues

DeBDE was not found in 5 human adipose tissue samples obtained from a hospital in Osaka in 1985-86. The limit of determination was < 50 llg/kg fat (yY atanabe, 1987; Watanabe et a!., 1987a). DeBDE was detected at concentrations of up to 5 llg/kg in 2 out of 40 samples of human hair obtained from barber shops in El Dorado and Magnolia, Arkansas (where the chemical is manufactured) in 1978 (DeCarlo, 1979). In the USA, Cramer et a!. (1990a,b) studied PBDD/PBDF levels in human fat tissue samples during 1987 (National Human Adipose Tissue Survey). The 865 specimens were combined to form 48 composites based on 9 census divisions and their age groups. The PBDD/PBDF analysis was carried out using HRGC/HRMS. No PBDD/PBDF were found (detection limit of 1-40 ng/kg, depending on congener). Identification of PBDE was based on comparison of full scan mass spectra of the samples with available standards, application of SIM techniques to compare theoretical ion ratios with observed ion ratios, and measurement of fragment losses from molecular ion clusters. Five samples were also monitored for DeBDE. No DeBDE was detected in 2 out of 5 samples; a weak DeBDE response was found in 1 out of 5 samples, and, in 2 out of 5 samples, DeBDE was estimated at 400 and 700 ng/kg, respectively.

5.2.2 Occupational exposure

Wipe samples collected during an industrial hygiene survey in a DeBDE manufacturing plant in the USA, indicated that workers 2 in the reactor area were exposed to 3.6 mg DeBDE/cm • Personal

107 EHC 162: Brominated diphenyl ethers

samples collected from workers in the mill area indicated that the airborne levels of DeBDE ranged from 0.08 to 0.21 mg/m3, as a 8-h time-weighted average. Following a spill in the mill area, personal airborne levels ranged from 1.3 to 1.9 mg/m3 (Bialik, 1982). Human exposure to DeBDE occurs in the course of manufacture and use. Surveys have determined employee time­ weighted average exposures of 1-4 mg/m3 in air with excursions up to 42 mg/m3 during short tasks. More than 90% of the particles in air were smaller than 10 J.Lm in diameter. On the basis of its classification as a nuisance material by OSHA, the recommended workplace environmental exposure level in air is 5 mg/m3 (8-h time-weighted average for a 40-h week) {NTP, 1986) (see also section 4.2). Studies on worker exposure to PBDF/PBDD during the production of polymers containing PBDE are given in section 4.3.3.2.

108 6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

6. 1 Absorption and elimination

Three male and 3 female Sprague-Dawley rats were admin­ istered orally 14C-labelled DeBDE suspended in corn oil. The elimination in urine and expired air was measured at 24-h intervals over a 16-day period. Less than 1% was found in urine and expired air. The principal route of elimination was via the faeces. Within 24 h, 90.6% of the 14 C activity was excreted and all the 14C was accounted for by day 2 of the study. The data indicate that there is minimal absorption of DeBDE by the gastrointestinal tract (Norris eta!., I973, I974, I975a,c; Dieter, I979). As a supplement to the carcinogenicity studies (sections 7.3 and 7. 7), additional experiments were conducted to quantify DeBDE absorption from the gastrointestinal tract of male rats and to determine the effect of dose on absorption. Radiolabelled 14C­ DeBDE (97.9-99.2%) was diluted with unlabelled DeBDE to yield the desired concentrations. DeBDE was mixed in the diet at approximate concentrations of 250, 500, 5000, 25 000, or 50 000 mg/kg, or was administered by intravenous injection. Animals were preconditioned by being fed diets containing the respective dose of unlabelled DeBDE for 7 days before being fed diets containing 14C-DeBDE for I day, then being returned to diets containing unlabelled material for the remainder of the holding period. Results indicated that, after exposure to all doses in the diet, more than 99% of the radioactivity recovered was eliminated in the faeces within 72 h. Excretion in the urine accounted for approximately O.OI% or less of the dose. The high 14 C-DeBDE content of the gastrointestinal tissues was attributed to intimate contact with the diet. Concentrations of DeBDE in other tissues were near the limits of determination. After an intravenous dose of I mg/kg, 61% of the recovered radioactivity was eliminated in the faeces in 72 h and approximately O.I% in the urine. Estimates indicate that 0.33% ± 0.19% of the 50 000 mg/kg dose was absorbed. Data for the 25 000 mg/kg diet showed that

109 EHC 162: Brominated diphenylethers

the percentage of the dose absorbed was not significantly different from that of the highest dose. Radioactivity present in the liver following exposure in the diet was confirmed as DeBDE. However, the minimal absorption of DeBDE from the gastro­ intestinal tract, and, presumably, from other potential routes of exposure may explain the low toxicity of DeBDE (NTP, 1986; El Dareer eta!., 1987).

6.2 Distribution

The distribution of radioactivity was measured in various tissues by Norris et a!. (1973, 1975a,c). On day 16, no 14 C­ activity was found in the tissues, with the exception of 0.01% of the administered dose/g in the adrenal glands and 0.06% in the spleen. In studies in which concentrations of 14C-labelled DeBDE of 250-50 000 mg/kg diet were fed to male Fischer 344 rats, more than 99% of the radioactivity was recovered in the faeces and intestinal contents (see section 6.1). The liver contained approximately 0.5% of the consumed dose, 24 h after feeding, and this declined to 0.016% after 72 h. Labelled material was extracted from the liver and found to be mainly unchanged DeBDE. Trace amounts of label were found in the kidneys, spleen, lung, brain, muscle, fat, and skin. Seventy-two hours following an intravenous dose of 14C-labelled DeBDE, the faeces and gut contents contained 74% of the dose, suggesting significant biliary excretion. Of the extracted faecal label, 63% were metabolites of DeBDE and 37% unchanged DeBDE. Labelled materials were found in the liver, kidneys, and lungs and in lower concentrations in muscle, skin, and fat (NTP, 1986; El Dareer et a!., 1987). Rats were administered DeBDE in the diet at 0, 25, or 50 g/ kg to determine the concentrations of DeBDE in the liver. The mean concentrations in the livers were 0.21 ± 0.43 (9), 2.09 ± 0.89 (8), and 8.6 ± 2.83 mg/kg liver (20), respectively. The number of livers studied is given in brackets (Rogers & Hill, 1980) (no details available).

110 Decabromodiphenyl ether

6.3 Retention and turnover

A 2-year tissue accumulation study on the rat was carried out. Groups of 3 male and 3 female Sprague-Dawley rats were maintained on diets providing 0, 0.01, 0.1, or 1.0 mg DeBDE (FR-300 BA)/kg body weight per day for designated periods of time. The tissues/organs analysed for total bromine content were serum, adipose tissue, liver, kidneys, skeletal muscle, and testes (see section 7.3.1.2). Interim results after 10, 30, 90, 180 days, and 12 and 18 months of exposure showed that the total bromine values in serum, liver, kidneys, skeletal muscle, and testes were comparable with the control values. The mean total bromine content of adipose tissue showed a time- and dose-related (significant) increase, especially in the groups receiving 0.1 and 1.0 mg DeBDE/kg per day. Although there was a continuing increase in total bromine content, the concentrations in adipose tissue of rats ingesting 0.01, and 0.1 mg DeBDE/kg per day for 23-24 months were 2.8 ± 0.9, and 7.5 ± 3.0 mg/kg, respectively, compared with 2.0 ± 0.2 mg/kg for the control rats. In the liver, the concentrations for the controls and the rats treated with 1.0 mg/kg were 2.9 ± 0.2 and 5.9 ± 1.1, respectively. In serum, after 23-24 months, the concentrations for the 4 groups were 8.0 ± 1.2 (control), 9.1 ± 1.1 (0.01 mg/kg), 7.9 ± 0.6 (0.1 mg/kg) and 8.1 ± 1.0 (1.0 mg/kg) (Norris et al., 1974, 1975a; Kociba et al., 1975,1975a). The elimination of bromine from tissues was studied in male Sprague-Dawley rats maintained for 90 days on a diet providing a dose of 1.0 mg DeB DE/kg per day, and then on a control diet. Four rats out of each group were sacrificed on the last day of exposure or after a recovery period of 0, 10, 30, 60, or 90 days. Serum, kidneys, adipose tissue, and liver were analysed. The low level of total bromine accumulated in adipose tissue remained unaffected during 90 days of recovery. Bromine was cleared from the liver within 10 days of recovery (Norris et al., 1974, 1975a,c). The half-life for the disappearance of 14C-activity from the body of DeBDE-treated rats was less than 24 h. The principal route of elimination was the faeces. No sex-related differences were found. 14C-activity was rapidly cleared in DeBDE-treated rats.

111 7. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS

The toxicological information on DeBDE has been summarized in several publications including: Norris et al. (1973, 1974, 1975a,b,c), AIHA (1981), and NTP (1986).

7.1 Single exposure

7. 1. 1 Oral: Rat

Intragastric intubation of single doses of 126-2000 mg commercial DeBDE/kg body weight, as a 10% corn oil suspension, to female Sprague-Dawley rats (Spartan strain), did not produce any indications of toxicity or gross pathological changes during a 14-day period (Norris et al., 1973, 1974, 1975a,c). Groups of 5 male Spartan rats received single oral doses of up to 5 g/kg body weight, by gavage, as suspensions in corn oil. No deaths occurred and the animals showed normal weight gain during

a 14-day observation time. The acute oral LD50 in rats was > 5 g/kg body weight (Great Lakes Chemical Corporation, undated b).

7. 1. 2 Dermal: Rabbit

Commercial DeBDE was applied and to the occluded, clipped, intact skin of 2 male and 2 female New Zealand white rabbits, each at a dosage of 200 or 2000 mg/kg body weight, for 24 h. Observation time was 14 days. No mortality occurred. The acute

dermal LD 50 in rabbits was > 2 g/kg body weight (Great Lakes Chern. Corp., undated b).

7. 1.3 Inhalation: Rat

Groups of 10 male and 10 female Spartan rats were exposed for 1 h to concentrations of commercial DeBDE of 2 or 48.2 mg/litre air and subsequently observed for 14 days. All rats survived. At 2 mg/litre, salivation was noted in 2 rats on the first

112 Decabromodiphenyl ether

day, but, from there on, all the rats in this group appeared normal, except one with respiratory difficulties and another with ocular discharge during the observation period. At 48.1 mg/litre, eye squint and increased motor activity were noted in the animals up to day 4. Respiratory difficulties were noted in 2 rats on days 3-6 and in one rat on day 8 and one on day 7. A few rats showed eye squint and ocular discharge on days 7-12. All rats were normal on day 14. The acute inhalation LD~ in rats was > 48.2 mg/litre (Great Lakes Chemical Corporation, undated b).

7.2 Short-term exposure

7.2.1 Oral

7.2. 1. 1 Mouse

In a 14-day study, groups of 5 B6C3F1 mice, of each sex, were exposed to DeBDE (99%) in the diet at concentrations of 0, 20, 50, or 100 g/kg. No effects on health, survival, or body weights were observed and no compound-related clinical signs or gross pathological effects were reported (NTP, 1986). In a 13-week study, groups of 10 male and 10 female B6C3F1 mice were administered DeBDE (two lots of DeBDE were used; one of 99% and the other > 97%) in the diet at 0, 31, 62, 12.5, 25, or 50 g/kg, for 13 weeks. No evidence was found for compound-related effects on physical appearance, behaviour, food consumption, body weight gain, survival, and gross and microscopic pathology. This study was used to establish the dose levels for the long-term study (Rutter & Machotka, 1979; NTP, 1986).

7.2.1.2 Rat

In 3 separate, 28-day feeding studies, each with groups of 10 male and 10 female Charles River CD rats, commercial DeBDE was administered at 0, 100, or 1000 mg/kg diet. The rats were observed for appearance, mortality, food consumption, body weight gain, and organ weights. After sacrifice, gross pathological and microscopic examinations of the liver, kidneys, and thyroid were carried out. Adverse effects or lesions associated with

113 EHC 162: Brominated diphenyl ethers

DeBDE administration were not found in these 3 rat studies. The total bromine contents of the liver, and adipose tissue were determined and a slight increase in bromine concentration was found at the highest dose level (Great Lakes Chemical Corporation, undated b) (no details available).

Groups of 5 male Sprague-Dawley rats were administered a diet containing 0, 0.01, 0.1, or 1.0% [equivalent to 0, 8, 80, or 800 mg DeBDE (77.4% DeBDE, 21.8% NBDE, and 0.8% OBDE)/kg body weight per day], for 30 days. No influence on food intake or body weight gain was found. No haematological changes were observed in the 8 and 80 mg/kg dose groups, but, at 800 mg/kg, there were decreases in packed cell volume and red blood cell count. Urinalysis parameters were not affected at any dose level. No differences in heart, testes, brain, and kidney weights were observed. Enlarged livers were found in rats exposed to 80 and 800 mg DeBDE/kg. The liver lesions consisted of centrolobular cytoplasmic vacuolization. Furthermore, in the rats receiving 80 and 800 mg/kg, hyaline degenerative cytoplasmic changes in the kidneys and thyroid hyperplasia were found. At a dietary level of 0.1 g/kg (equivalent to 8 mg/kg body weight), no treatment-related changes in the liver or thyroid, or other changes were found. (Remark: limited histopathology was carried out) (Sparschu et al., 1971; Norris et al., 1973, 1974, 1975a; Kociba et al., 1975a).

In a 14-day study with DeBDE (99%) administered in the diet to Fischer 344/N rats at concentrations of 0, 5, 20, 50, or 100 g/kg, no effects were seen on health, survival, and body weight, and no compound-related clinical signs or gross pathological effects were observed. Similarly, no toxic effects were seen in a 90-day study in which doses of DeBDE (> 97%) of 0, 3.1, 6.2, 12.5, 25, or 50 g/kg were administered in the diet. No effects on survival, body weight, or feed consumption were observed. No gross or microscopic effects were reported. Liver weights were not recorded in these studies, but, in subsequent studies, liver weights were significantly increased in Fischer 344/N rats at dose levels of 25 and 50g DeB DE (92% )/kg diet, for 14 days (NTP, 1986).

114 Decabromodiphenyl ether

7. 2. 2 Inhalation

7.2.2.1 Rat

Pulmonary tissue response and pulmonary clearance of commercial DeBDE were evaluated following intratracheal administration of the dust to rats. The study was conducted to evaluate the possible health hazards for man from inhalation of the dust generated during the production and handling of DeBDE. Fifty male, Sprague-Dawley rats were given an intratracheal injection of 20 mg DeBDE (77 .4%) dust (length mean diameter 2.65 ~-tm, surface mean diameter 2.91 ~-tm, and volume mean diameter 3.17 ~tm) suspended in 1 ml of rat serum. A control group of 35 rats received only the serum vehicle. The rats were observed for appearance, demeanour, and body weights. Groups of 5 treated and 2 control rats were killed on days 3, 10, 30, 91, and 365 for determination of total bromine content in the lungs. The calculated DeBDE equivalent values were used to determine the half-life of DeBDE in lungs, which was determined to be 150 days. To assess the respiratory tissue response, gross and histopathological examinations were conducted on rats killed on days 10, 30, 416, and 556 and on rats that died. No untoward effects were observed, except on days 10 and 556 (but not on days 30 and 416): the lungs of treated rats contained scattered focal aggregates of alveolar macrophages showing clear, angulated, cytoplasmic vacuoles or spaces, which probably represented the location of the dust particles. A very slight focal thickening of the interalveolar septae was noted in 2 out of 5 rats. Particles were not present in the regional lymph nodes. No evidence of fibrosis or other proliferative response was detected in the lungs or regional lymph nodes (Jersey et al., 1976).

7.3 Long-term exposure

7.3.1 Oral

7.3.1. 1 Mouse

A two-year study was carried out on B6C3F1 mice. The animals were administered DeBDE in the diet at concentrations of

115 EHC 162: Brominated diphenyl ethers

0, 25, or 50 g/kg, for 113 weeks (NTP, 1986) (for details of the study see section 7. 7 .1.1).

7.3.1.2 Rat

A long-term/carcinogenicity study was carried out on Sprague­ Dawley rats administered daily doses of 0, 0.01, 0.1, or 1.0 mg DeBDE/kg body weight in the diet for 2 years (Kociba et al., 1975, 1975a; Norris et al., 1975a,b). In another 2-year study, Fischer 344 rats were administered DeBDE at 0, 25, or 50 g/kg diet (NTP, 1986) (for details of these 2 studies see section 7.7.1.2).

7.4 Skin and eye irritation; sensitization

7.4. 7 Skin irritation

Skin irritation studies conducted with commercial DeBDE, applied as a dry solid (500 mg) on the shaved skin (under occlusion) of 2 groups of 3 New Zealand white rabbits caused no irritation on intact skin and no, or only slight, erythematous and oedematous responses on abraded skin, after a single exposure for 24 h and an observation period of 72 h. A comparable study on 3 male and 3 female New Zealand white rabbits in which 500 mg DeBDE was applied on intact or abraded skin showed no skin irritation. Repeating the exposures of intact skin for 5 days/week for 2 weeks or to abraded skin for 3 days did not alter the response (Norris et al., 1973, 1974, 1975a,c; Great Lakes Chemical Corporation, undated c).

7.4.2 Eye irritation

Eye irritation studies on 3 male and 3 female New Zealand White rabbits showed that 100 mg Saytex 102/eye, applied as a dry solid, caused only transient irritation (redness and chemosis) of the conjunctival membranes. The cornea, iris, and lens were unaffected (sodium fluorescein and UVR were used). After 24 h, the eyes had recovered. The observations were made at 1, 24, 48, 72 h, and 7 days after treatment (Norris et a!., 1973, 1974, 1975a,c; Ethyl Corp., 1986; Mallory et a!., 1986; Great Lakes Chemical Corporation, undated c).

116 Decabromodipheny/ ether

7.4.3 Sensitization

Repeated application of a suspension of 5% DeBDE (77.4% DeBDE, 21.8% NBDE, 0.8% OBDE) in petrolatum, 3 times a week for 3 weeks, to the skin of 50 human volunteers did not result in skin sensitization reactions during the sensitizing period or, on challenge 2 weeks following the last application. Skin irritation was observed in 14 out of the total 450 applications (11 of the reactions were classified as very slight and 3 as mild erythema). These reactions were seen in 9 out of the 50 persons (Norris et al., 1974, 1975a,c; Dow Chemical Comp. USA, 1978).

7.4.4 Ch/oracnegenic activity

Chloracnegenic activity was studied on the ear of each of 4 New Zealand White male and female rabbits. The test material (Saytex 102) was administered once daily at 0.1 ml/day, 5 times per week, for 4 weeks, at concentrations of 1, 10, 100, or 1000 g/kg, in chloroform. Observations were recorded prior to the initial dose and at 7, 14, 21, and 28 days of dosing. Saytex 102 as a 10% chloroform solution caused a slight erythematous response and slight exfoliation, but no chloracne was observed during the study (Naismith & Matthews 1981). In the period 1971-74, approximately 40 samples of DeBDE (pilot plant samples), mother liquor, mother liquor still pot residue, and still bottom samples were studied for their chloracnegenic activity. In these studies, the samples (0.1 ml) were applied as such, or as a 5 or 10% solution in chloroform, on the rabbit ear, 5 days per week for 4 weeks. The samples of DeBDE did not induce any responses, but responses to the mother liquor and still bottom samples were positive, except in a few cases where the result was equivocal (Rampy, 1971-74).

7. 5 Reproductive toxicity, embryotoxicity, and teratogenicity

7. 5. 1 Reproductive toxicity

A one-generation reproduction study was performed in which 10 male, and 20 female, Sprague-Dawley rats at the two lower

117 EHC 162: Brominated diphenyl ethers

dose levels (3 and 30 mg/kg body weight) and 15 male and 30 female rats at the higher dose level (100 mg/kg body weight) were given commercial DeBDE with the diet (weekly adjustment), for 60 days prior to mating, 15 days during mating, and subsequently throughout gestation and lactation. Twenty male and 40 female rats served as controls. No signs of toxicity were observed in the adult rats or the neonates during the study or at necropsy. Unaffected parameters included body weight gain and food consumption by adults, reproductive parameters (the percentage pregnant and neonatal growth, survival, and development), preterminal urinalysis and clinical chemistry in adult rats, gross examination of all adult and weanling rats, and microscopic examination of tissues from both age groups. No cytogenetic changes were observed in the bone-marrow of parents and weanling rats. Thus, no toxicological manifestations were associated with the ingestion of 100 mg DeBDE/kg in this reproduction study (Norris eta!., 1975c; Schwetz eta!., 1975).

7.5.2 Teratogenicity

Pregnant female rats were given 0, 10, 100, or 1000 mg commercial DeBDE/kg body weight, suspended in corn oil, by intragastric gavage, on days 6-15 of gestation. Maternal food consumption and body weight did not differ from those of the controls. Liver weights of the mothers were comparable with those of the control animals. The position and number of fetuses in utero, the number of corpora lutea, individual pup weight, crown-rump length, and sex ratio, were similar to those of the controls-. A significant increase in resorptions was found at low dose levels, but not at the high dose level. No gross external abnormalities were seen in the fetuses of dams treated at any dose level. Soft tissue and skeletal examinations revealed an increased number of litters with subcutaneous oedema and delayed ossification of bones of the skull of fetuses of dams treated with 1000 mg/kg, but not with 100 mg/kg body weight. Analysis of maternal and fetal livers for total bromine revealed a significantly increased concentration in maternal livers of rats treated with 1000 mg/kg. Treatment with 100 mg/kg or less did not produce any increase in total bromine contents. No increase in total bromine contents was observed in

118 Decabromodiphenylether

the livers of fetuses from dams receiving any of the dose levels of DeBDE (Norris et al., 1973, 1974, 1975a; Hanley, 1985; US EPA, 1989).

7.6 Mutagenicity and related end-points

7. 6. 1 Mutation

A technical product, HFO 102, was tested in a Salmonella typhimurium assay with the strains TA 98, TA 100, TA 1535, and TA 1537 with, or without, metabolic activation. The HFO 102 was not completely soluble in DMSO at a concentration of 10 mg/litre. However, the suspension was used for the test and for preparation of the solutions. The dose levels that were tested were 0.4, 4.0, 40, and 1000 ~-tglplate. No evidence for mutagenic activity was found (Shoichet & Ehrlich, 1977). Results of studies with Saccharomyces cerevisiae with, or without, liver microsomal enzyme preparations, were also negative (no details) (Great Lakes Chemical Corporation, undated b).

Commercial DeBDE in concentrations of 100-10 000 ~-tg/plate was not mutagenic in Salmonella typhimurium, TA 100, TA 1535, T A 1537, and TA 98 strains, in the presence, or absence, of an exogenous metabolic system from Aroclor 1254-induced male rat liver S9 and male Syrian hamster liver S9 (NTP, 1986).

7. 6. 2 Chromosomal effects

Cytogenetic examination of bone marrow cells, taken at necropsy from the femur of the parent animals from a reproduction study (see section 7.5.1) as well as from the neonates at weaning, showed no increase in cytogenetic aberrations compared with the controls (Norris eta!., 1975c) (no details). Commercial DeBDE was not mutagenic in the mouse lymphoma L5178Y/TK+/- assay in the presence, or absence, of Aroclor 1254-induced male F344 rat liver S9. Tests for cytogenic effects in Chinese hamster ovary cells indicated that commercial DeBDE does not cause chromosomal aberrations or sister­ chromatid exchanges in either the presence or absence of S9,

119 EHC 762: Brominated diphenylethers

prepared from livers of Aroclor 1254-induced male Sprague­ Dawley rats (NTP, 1986).

7. 7 Carcinogenicity

7.7. 7 Oral

7. 7. 1.1 Mouse

Groups of 50 male and 50 female B6C3F1 mice (nine weeks old) were fed 0, 25, or 50 g DeBDE (purity 94-99%; no brominated dioxins or furans were found)/kg diet for 103 weeks; all survivors were killed in weeks 112-113. The average daily consumption of DeBDE was estimated to be 3200 mg/kg for low­ dose and 6650 mg/kg for high-dose male mice and 3760 mg/kg for low-dose and 7780 mg/kg for high-dose female mice. Body weights and survival of treated animals were comparable with those of the controls. Non-neoplastic lesions observed in treated mice were granulomas in the liver of low-dose males and hypertrophy in the liver of low- and high-dose males. The combined incidence of hepatocellular adenomas and carcinomas was significantly increased in males: control 8/50, low-dose 22/50, and high-dose 18/50 (but not increased in comparison with historical control groups); the combined incidence of thyroid gland follicular-cell adenomas and carcinomas was increased, but not significantly, in treated males: control 0/50, low-dose 4/50, high­ dose 3/50; females: control 1/50, low-dose 3/50, high-dose 3/50. Follicular-cell hyperplasia of the thyroid gland was increased in both groups of treated male and female mice (NTP, 1986; Huff et al., 1989).

7.7. 1.2 Rat

Groups of 25 male, and 25 female, Sprague-Dawley rats, 6-7 weeks of age, were fed 0, 0.01, 0.1, or 1.0 mg DeBDE/kg body weight (purity DeB DE 77.4%, nonabromodiphenyl ether 21.8%, octabromodiphenyl ether 0.8%) in the diet for 100-105 weeks. Additional groups of 10-34 rats/sex per dose level were killed at various times during the study to investigate the accumulation of total bromine in the tissues. Ingestion of up to 1.0 mg DeBDE/kg did not influence survival rates; appearance, mean body weights,

120 Decabromodiphenyl ether

feed consumption, haematology, urinalysis, clinical chemistry, and organ weights of treated groups were similar to those of controls. No discernible toxicological effects were produced by DeBDE and no significant differences in the number of rats developing tumours, the total number of tumours, or the specific type of tumours were observed between treated and control groups, when evaluated by the Fisher's exact probability test. Adrenal phaeochromocytomas were the most frequent tumours in the male rats in all groups. During the study, there was a slight build up of the total bromine content in the tissues of rats ingesting the 2 highest dose levels, as measured by neutron activation analysis. However, the source of bromine may, or may not, have been DeBDE, because NBDE and OBDE were also present in the product. Serum, muscle, and kidneys did not show any increase in total bromine content. In the liver, low-level, steady-state conditions were attained by 12 months. Adipose tissue showed a time- and dose-related increase in total bromine content, subsequent to ingestion of 0.1 or 1.0 mg/kg. The total bromine content of adipose tissue of rats ingesting 0.01 mg/kg for 2 years was 2.8 ± 0.9 mg/kg compared with a control value of 2.0 ± 0.2 mg/kg (section 6.3) (Kociba et al., 1975, 1975a; Norris et al., 1975a,b). [The IARC Working Group (1990) noted the very low dose levels used]. Groups of 50 male, and 50 female, Fischer 344/N rats, 7-8 weeks of age, were fed DeBDE (purity 94-99%; no brominated dioxins or furans were found) at 0, 25 or 50 g/kg diet, for 103 weeks; all survivors were killed in weeks 111-112. The average daily consumption of DeBDE was estimated to be 1120 and 2240 mg/kg for low-dose and high-dose male rats, respectively, and 1200 and 2550 mg/kg for low-dose and high-dose female rats, respectively. Body weights of treated rats were not significantly different from those of the controls. Thrombosis and degeneration of the liver, fibrosis of the spleen, and lymphoid hyperplasia were observed in high-dose male rats. Significant increases were observed in the incidence of neoplastic nodules of the liver (adenomas) in treated males: control 1/50; low-dose 7 /50; high­ dose 15/49 and females: control 1150; low-dose 3/49; high-dose 9/50. No differences in the incidence of hepatocellular carcinomas were seen among the groups. The incidence of acinar-cell adenomas of the pancreas in males was: control 0/49; low-dose

121 EHC 162: Brominated diphenylethers

0/50; high-dose 4/49. The difference between the controls and the high-dose group was not significant. A high incidence of mononuclear-cell leukaemia was observed in treated and control rats of both sexes (NTP, 1986; Huff et al., 1989).

7.8 Other special studies

7.8.1 Liver

Carlson (1980a) administered commercial DeBDE (in corn oil), by gavage, at a dose of 0.1 mmol/kg body weight to male Sprague-Dawley rats (200-250 g) for 14 days. Twenty-four hours after the last (seventh) dose, the liver/body weight ratio increased. Koster et at. (1980) found no evidence of a porphyrinogenic action after exposure of cultures of chick embryo liver cells to a concentration of 5 ,_,.g DeBDE (in DMSO)/ml medium with, or without, pretreatment with naphthotlavone, an inducer of P450, P448, and of delta-levulinic acid synthethase. A sample of DeBDE, obtained from the NTP repository, was administered by gavage (vehicle not clear) at 1500 mg/kg body weight to 9, three-month-old, female Sprague-Dawley (CD) rats, 21 h and 4 h before they were killed. No changes were observed in hepatic cytochrome P450 content, hepatic DNA damage, as determined by alkaline elution, hepatic ornithine decarboxylase activity, or serum alanine aminotransferase activity (Kitchin et al., 1992).

7.8.2 AfisceHaneous

Hefner (1973) studied, in an in vitro model, the rupture of erythrocyte membranes (haemolysis) induced by dust particles. The test approximates the in vivo rupture of the secondary lysosomal membranes. Fibrogenic dusts are capable of rupturing the erythrocyte membrane, while non-fibrogenic dusts are not. On the basis of the in vitro model, DeBDE of the particle size studied (shown by optical microscopy to have a 2.65 ,_,.m number length mean diameter with 94.5% of the particles being 3.77 ,_,.m and below) appears to be non-fibrogenic (only 0.1% haemolysis) at 1- 15 mg dust/ml suspension and time from 15 to 120 min.

122 Decabromodiphenyl ether

7.8.3 Toxicity of soot, char, and other waste products from com­ bustion of DeBDE-containing polymers

7.8.3. 1 Acute oral toxicity

Groups of 5 male, and 5 female, Sprague-Dawley rats were administered a mixture of soot and char (61/39%), generated from the combustion of high-impact polystyrene, as a single dose, by gavage at O(vehicle), 0.5, 5.0, 50, 500, or 2000 mg/kg body weight. These amounts were given in 10 ml 1% methyl cellulose/kg body weight. Observation time was 28 days. Body weight gain, mortality, and weights of 10 organs were studied, and these organs in the control and 2000 mg groups were also examined microscopically. No overt signs of toxicity were

observed. The acute oral LD50 was > 2 g/kg body weight (Fulfs & Dahlgren, 1987a). The acute toxicity of the combustion products of a matrix composed of high-impact polystyrene, DeBDE, and antimony trioxide was investigated. Six dose groups of 5 male and 5 female rats were treated, by gavage, with 0, 0.5, 5, 50, 500, or 2000 mg/kg of combined soot and char, generated from the combustion of the flame retarded high-impact polystyrene (HIPS) suspended in 1% methyl cellulose and observed for 28 days. No animals died during the course of the study and no clinical signs of toxicity were observed. No histological lesions were detected in the following organs examined: thyroid, parathyroid, and adrenal glands, spleen, gonads, heart, liver, lung, brain, kidneys, and

thymus. The LD50 was > 2000 mg/kg body weight (Fulfs & Dahlgren, 1987b; Pinkerton et al., 1989). Undiluted solids from mother liquor (waste tars) were tested for acute oral toxicity in rats. No acute oral lethality was seen with 0.126 g/kg body weight in corn oil, but 100% mortality was found, with 0.5 g in water. The animals displayed tremors (Norris, 1971).

7.8.3.2 Skin irritation and comedogenicity

Soot and char generated from the combustion of high-impact

polystyrene retarded with, or without, DeBDE and Sb20 3 were tested for their comedogenicity using a New Zealand albino rabbit

123 EHC 162: Brominated diphenyl ethers

ear bioassay (Draize, 1979). The soot and char samples were mixed in different ratios. The dose levels were; 0.001, 0.003, 0.005, 0.008, 0.01, 0.03, 0.05, 0.08, and 0.1 g. The highest dose level (0.1 g) of the mixture was actually in excess of the amount that remained on the ear. The materials were applied in 0.1 ml of water. Five male rabbits, with 2 healthy ears each, were randomly selected for these studies and the original design required 10 exposure levels, 1 per ear. Dosing was continued for 5 consecutive days. Ears were checked to grade the erythema on day -1 and day 0, and then daily, and the final grading was done on the day following the last dosing. The results showed that, without flame retardants, very slight to well defined erythema occurred with doses of 0.005 g and higher. In cases where the polymer was flame retarded, the effect was stronger, very slight to moderate/severe erythema occurred with doses of 0.001-0.003 g or more (see Table 24) (Fulfs 1987a,b).

Table 24. Skin Irritation by soot or char generated from the combtnation of HIPS with, or without, DeBOE

Soot/char Mixture Dose Erythema score soot/char

High impact 61/39% 0.005 g and score 1-2 (increasing polystyrene higher with dose level from day 2 onwards)

H1gh impact 47/53% 0.003 g and score 1-3 (increasing polystyrene with higher With dose level, from DeBOE and antimony day 1) trioxide 0.001 g and same result, increasing higher from day 3

Two groups of four (mainly 2 male and 2 female) New Zealand white rabbits were used to test a mixture of soot and char (61139%), generated from the combustion of high-impact polystyrene treated without flame retardants, in a rabbit ear comedogenicity bioassay. Daily dose levels of 2, 5, 8, 20, or 50 mg of the mixture were administered. Each daily dose was rubbed with 0.1 ml of water on the inner surface of the pinna of

124 Decabromodiphenyl ether

one ear of the respective rabbit. The animals were dosed 5 days per week for a total of 4 weeks. The total cumulative dose levels were 40, 100, 160, 400, and 1000 mg. The ears were graded for irritation (Draize test) and for hyperkeratosis (Adams test). During the study, dermal irritation was found in all treated groups with a score of 1-2. No comedogenic (score 0) responses were observed on any of the ears. A slight increase in hyperkeratosis of the sebaceous follicles was seen during histopathological examination of the skin in the animals treated with the 2 highest dose levels. No evidence of overt toxicity was seen among any of the animals tested (Fulfs & Dahlgren, 1987c; Pinkerton et al., 1989). A similar study was carried out with a combined soot and char (4 7/53%) mixture, generated from the combustion of HIPS flame retarded with DeBDE and antimony trioxide. The results were comparable with those of the combustion products of HIPS without flame retardants. There was no microscopic evidence of any significant hyperkeratotic response (Fulfs & Dahlgren, 1987d). Undiluted solids from mother liquor (waste tars) were tested for skin irritation in rabbits. Slight skin irritation was observed at a dose of 1.1 g/day for 3 days (Norris, 1971).

7. 8. 3. 3 Eye irritation

Solids from mother liquor (waste tars) were tested for eye irritation. The material is a mixture of brominated DeBDE (Br = 7-10). A dose of 0.1 g of the mixture caused severe eye irritation and slight corneal injury (Norris, 1971).

125 8. EFFECTS ON HUMANS

8.1 General population exposure

No data are available.

8.2 Occupational exposure

8. 2. 1 Skin sensitization

Human volunteers (80 males and 120 females) were treated with 9 induction patches of 2 batches of DeBDE, identified as DBD0-1 and XD 8186.02. The first sample was evaluated as such, and the second as a 2% (W IV) aqueous solution. The upper arm was used in the males and the upper back in the females. The patches were applied once every 2 days and the substance left in contact with the skin for 24 h, after which it was removed. After the application of 9 patches, there followed a non-patching period of 12 days, after which the challenge patch was applied to detect sensitization. A new skin site was used for this 24-h patch. After removal of the patch, reactions were observed after 24 and 48 h. This study did not reveal any evidence of skin sensitization with either test material in any of the subjects (Industrial Bio-test Laboratories, 1975).

8. 2. 2 Neurotoxicity

A health assessment of workers exposed to po!ybrominated biphenyls and polybromodiphenyl ethers, e.g.. DeB DE, during manufacture revealed a higher than normal prevalence of primary hypothyroidism and a significant reduction in sensory and fibula motor velocities; no other dermatological or neurological effects were seen. The authors could not conclude whether these effects were caused by DeBDE or by PBB, which was also produced (earlier) in the plant. DeBDE was not detected in the serum of the workers (Bahn et al., 1980).

126 Decabromodiphenyl ether

8.2.3 Epidemiological studies

The health of workers in facilities where flame retarded polymers were extruded has been evaluated in 3 studies, 2 at Celanese and 1 at General Electric (BFRIP, 1990). A study was conducted by Celanese Corporation in the late 1970s at their Bishop, Texas, facility. The primary purpose of this study, conducted by Tabershaw Associates, was to investigate the possible effects of employee exposure to formaldehyde. However, brominated flame retardants have been used at the facility since 1970, and, therefore, significant effects resulting from the use of these materials might also have been revealed by the study. No effects that might be attributable to the use of the brominated flame retardants were observed (EBFRIP, 1990). A more complete study was conducted by General Electric Plastics at their Mt. Vernon, Indiana, facility early in 1988. In the conclusions of the study, it is stated that "there appears to be no evidence that the workers in the study zone display any symptoms associated with exposure to dioxins or related substances. More critically, as a statistical group, the general medical examinations for these workers compare very favorably with the examination for the workers in the control zone or with published values for the general population". It is finally concluded that "the study gives reasons to continue to be observant but no reason to be alarmed" (EBFRIP, 1990). A comprehensive medical evaluation of workers involved in the processing of polymers containing brominated flame retardants was undertaken at the BASF facility in Ludwigshafen, Germany. In this study, some 40 potentially exposed workers and an equivalent number of workers from a control group were subjected to complete medical and psychological examination. The health of the workers compared favourably with workers in the control zones. None of the workers displayed symptoms associated with exposure to dioxin or related substances, therefore, it was concluded that the workers did not show any symptoms that could be associated with PBDD or PBDF emitted during the polymer processing. It should be kept in mind that there might also be exposure during the formulation of PBDE- containing polymers

127 EHC 162: Brominated diphenyl ethers

and from products made of these polymers. Furthermore, exposure to dusts may also occur (EBFRIP, 1990). Zober et al. (1992) carried out a morbidity study of extruder personnel with potential exposure to brominated dioxins and brominated furans. The presence of PBDF/PBDD in air was established through air-monitoring during the extrusion blending of polybutyleneterephthalate with DeBDE. Biomonitoring results of 42 workers (exposed during the period 1975-88) and immuno­ logical tests for exposed and 42 control employees were presented. Among potentially exposed men, 2,3,7,8-TeBDF/TeBDD concen­ trations in blood lipid ranged from nd to 112 and from nd to 478 ng/kg, respectively. The control workers had concentrations of 7 and 7-48 ng/kg respectively. Results of the immunological studies showed that the immune system of exposed workers was not adversely affected at these burdens of TeBDF/TeBDD for up to 13 years.

128 9. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD

Marine unicellular algae, Skeletanema castatum, 1halassiasira pseudanana, and Chiarella sp. were exposed to commercial DeBDE in 6 algal growth media. The duration of the exposure was 72 h for S. castatum and T. pseudanana and 96 h for Chiarella sp. The population density was estimated by cell counts using a haemocytometer. Inhibition by 1 mg DeBDE/litre acetone was less than 50% in all species (Walsh et al., 1987).

129 10. PREVIOUS EVALUATIONS BY INTERNATIONAL BODIES

An evaluation by IARC (1990) concluded that there is limited evidence for the carcinogenicity of DeBDE in experimental animals. No data were available from studies on the carcino­ genicity of DeBDE in humans. Overall evaluation: DeBDE is not classifiable as to its carcinogenicity for humans (Group 3).

130 NONABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

Nonabromodiphenyl ether is not manufactured or used. No data are available on the following topics:

• Environmental transport, distribution, and transformation • Environmental levels and human exposure • Kinetics and metabolism in laboratory animals and humans • Effects on laboratory mammals and in vitro test systems • Effects on humans • Effects on other organisms in the laboratory and field • Previous evaluations by international bodies.

1.1 Summary and evaluation

There is no database on which to make an evaluation.

1.2 Recommendations

Levels of contamination of commercial brominated flame retardants with nonabromodiphenyl ether should be minimized to avoid contamination of the environment and exposure of humans.

133 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2.1 Identity

Chemical structure:

6' 6 0 5

4' 4

Br9

Chemical formula: C12 H Br9 0 CAS registry number: 63936-56-1 Chemical name: pentabromo(2,3,4,5- tetrabromophenoxy )­ benzene Common name: nonabromodiphenyl ether (NBDE); nonabromodiphenyloxide Relative molecular mass: 880.37

Based on the chemical structure, there are three possible isomers of nonabromodiphenyl ether.

From: US EPA (1984, 1986).

134 Nonabromdiphenyl ether

2.2 Physical and chemical properties

No data are available.

2.3 Analytical methods

No specific data are available (see General Introduction section 2.1 and Table 2).

135 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

NBDE has not been reported to occur naturally (see General Introduction section 1.1).

3.2 Anthropogenic sources

3. 2. 1 Production levels and processes

Nonabromodiphenyl ether has been prepared from decabromodiphenyl ether by heating with NaSH in xylene at 130 oc for 2 h. The removal of the reactive Br in the ortho­ position of decabromodiphenyl ether led to the photostability of the product (Noguchi et al., 1977).

3.2.2 Uses

Nonabromodiphenyl ether is not used commercially as a flame retardant. It is present as an impurity in OBDE at a concentration of 10%.

136 OCTABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

Pure octabromodiphenyl ether is not manufactured or used. No data are available on the following topics:

• Kinetics and metabolism in laboratory animals and humans • Effects on humans • Effects on other organisms in the laboratory and field • Previous evaluations by international bodies.

1.1 Summary and evaluation

1. 1. 1 Identity, physical and chemical properties

Commercial OBDE is a mixture of approximately 11% PeBDE/HxBDE, 44% HpBDE, 31-35% OBDE, 10% NBDE, and 0.5% DeBDE. On the basis of the chemical structure, there are 12 possible isomers of OBDE and 24 possible isomers of HpBDE. The melting point varies from about 80 oc to > 200 °C. The vapour pressure is < w-7 mmHg. The solubility in water is

low and the n-octanol/water partition coefficient (log P0 w) > 5.5. The above variations in physical data may be explained by the differences in composition of the mixtures tested.

1. 1.2 Production and uses

The worldwide consumption of commercial OBDE per year is 6000 tonnes, 70% of which is used as a flame retardant in ABS for the production of computers and business cabinets. OBDE is the second most widely used PBDE flame retardant.

1. 1.3 Environmental transport, distribution, and transformation

Components of commercial OBDE have been found in aquatic sediment and human fat. Some lower brominated components (HxBDE and PeBDE) of commercial OBDE have been found in

139 EHC 162: Brominated diphenyl ethers

biota. OBDE has not been detected, but HpBDE and NBDE have generally not been looked for. Commercial OBDE components are likely to be persistent but, as bromination levels rise beyond HxBDE, they are increasingly unlikely to bioaccumulate. A bioaccumulation factor of less than 2 has been found in carp for a commercial OBDE product. Pyrolysis of commercial OBDE, as such, or of polymers with OBDE as a flame retardant (with, or without, Sb20 3) at 600 oc has been shown to produce PBDF and, in much lower concen­ trations, PBDD. Processing of ABS with OBDE/Sb20 3 under different conditions, showed that under normal processing conditions, only low levels of PBDF were formed. Under abusive conditions, the concentrations were much higher. PBDD concentrations were low in both cases.

1. 1.4 Environmental levels and human exposure

OBDE and the lower brominated components of commercial OBDE were not detected in water samples collected in Japan in 1987 and 1988. Sediment samples were also analysed and, in approximately 2-6% of the samples, OBDE was detected in concentrations ranging from 8 to 22 p,g/kg dry weight. Lower brominated components were also found in the sediment. OBDE was not detected in fish samples collected in Japan in 1987 and 1988. In the USA, samples of human fat were investigated for the presence of PBDF and PBDD in 1987. The samples were derived from 865 specimens combined to form 48 composite analogues. The composite design was based on 9 census divisions and 3 age groups. In these samples, PBDE were also identified and preliminary evidence showed the presence of OBDE at a frequency of 60% and an estimated concentration of up to 8000 ng/kg.

1. 1.5 Kinetics and metabolism in laboratory animals and humans

No data are available.

140 Octabromodiphenyl ether

1. 1.6 Effects on laboratory mammals and in vitro test systems

The acute toxicity of commercial OBDE for laboratory mammals is low. The substance is not irritant to the skin and gives only slight eye irritation in rabbits. In short-term toxicity studies (4-week and 13-week), rats administered dietary levels of 100 mg/kg had increased liver weights and microscopic changes characterized by enlarged centrolobular and midzonal liver parenchymal cells containing granular structures. These liver changes were more severe at higher dose levels, i.e., 1000 and 10 000 mg/kg diet. In addition, hyperplasia of the thyroid was seen. Total bromine content in the tissues increased during the study and decreased slowly during a recovery period. The liver changes were reversible. In an inhalation study with micronized dust of OBDE (8 h/day for 14 consecutive days), no effects were 3 3 observed with exposure to 1.2 mg/m , but a level of 12 mg/m caused the liver changes described in the oral studies. In rats, commercial OBDE at relatively low doses increased cytochrome P450 and induced hepatic microsomal enzymes, such as UDP-glucuronyl transferase and benz[a]pyrene hydroxylase. Commercial OBDE induced a porphyrinogenic effect in cultures of chick embryo liver cells. OBDE was tested for teratogenic potential in rats; at high dose levels (25.0 and 50.0 mg/kg body weight), resorptions, or delayed ossification of different bones and fetal malformations were observed. The malformations observed with doses of 25 mg/kg body weight and higher were most likely associated with maternal toxicity. These changes were not seen at dose levels of 15.0 mg/ kg body weight or less. In rabbits, there was no evidence for teratogenic activity, but fetotoxicity was seen at a maternally toxic dose level of 15 mg/kg body weight. Teratogenicity studies showed a no-effect level of 2.5 mg/kg body weight. In 28-day and 90-day rat studies, 100 mg OBDE per kg diet (equivalent to 5 mg/kg body weight) induced minimal effects in the liver. No no-effect level was established. Results of the mutagenicity tests including an unscheduled DNA assay, in vitro microbial assays, and an assay for sister chromatid exchange with Chinese hamster ovary cells were all negative.

141 EHC 162: Brominated diphenyl ethers

No long-term/carcinogenicity test results are available.

1. 1. 7 Effects on humans

No data are available.

1. 1.8 Effects on other organisms in the laboratory and field

Minimal data are available.

1.2 Conclusions

1.2.1 OBDE

Commercial OBDE is a mixture of hexa-, hepta-, octa-, and nonabromodiphenyl ether, all of which persist in the environment, largely bound to sediment. OBDE is widely incorporated in polymers as an additive flame retardant. Contact of the general population is with products made from these polymers. Exposure by extraction from polymers is unlikely. The acute toxicity of OBDE is low. There is no information on uptake and loss in mammals. OBDE is not teratogenic or mutagenic. Long-term toxicity and carcinogenicity studies are not available. Several components of commercial OBDE have been identified in human adipose tissue. The acute risk for the general population is likely to be low. Risk assessment of long-term exposure is not possible, because of the lack of relevant toxicity studies. No information is available to draw conclusions on occupational exposure to, or effects of, OBDE. Limited information is available on the toxicity of OBDE for organisms in the environment. Components of the commercial OBDE mixture with lower levels of bromination may bioaccumulate in organisms.

142 Octabromodiphenylether

1.2.2 Breakdown products

Formation of PBDF, and to some extent PBDD, may occur when OBDE, or products containing it, are heated to 400-800 °C. The possible hazards associated with this have to be addressed. Exposure of the general population to PBDF impurities in flame-retarded polymers is unlikely to be significant. Properly controlled incineration should not lead to the emission of significant quantities of brominated dioxins and -furans. Any uncontrolled combustion of products containing commercial OBDE can lead to the generation of unquantified amounts of PBDF/PBDD. The significance of this for both humans and the environment will be addressed in a future EHC on PBDF/PBDD.

1.3 Recommendations

1. 3. 1 General

• Best available techniques should be used in the manufacture of commercial OBDE, to minimize levels of hexa- and lower brominated congeners, because of their bioaccumulation potential in the environment. • Workers involved in the manufacture of OBDE, and products containing the compound, should be protected from exposure using appropriate industrial hygiene measures, monitoring of occupational exposure, and engineering controls. • Environmental exposure should be minimized through the appropriate treatment of effluents and emissions in industries using the compound or products. Disposal of industrial wastes and consumer products should be controlled to minimize environmental contamination with this persistent material and its breakdown products. • Incineration of materials, flame retarded with OBDE, should only be in properly constituted incinerators running under consistently optimal conditions. Burning by any other means may lead to production of PBDF and/or PBDD.

143 EHC 162: Brominated dipheny/ ethers

1.3.2 Further studies

Because the present toxicological database is inadequate to evaluate the hazards of commercial OBDE for humans and the environment, and, to support its use, the following studies should be carried out:

• Investigations on the bioavailability and ecotoxicity of sediment-bound components of commercial OBDE using the relevant organisms • Extended monitoring of environmental levels of components of commercial OBDE • Long-term toxicity and carcinogenicity studies of commercial OBDE • Monitoring of occupational exposure to commercial OBDE • Further investigations on the generation of PBDF under real fire conditions • Further studies on environmental biodegradation and photodegradation in compartments other than water • Investigation of possible methods and consequences of recycling of OBDE-containing polymers • Validation of analytical methods for OBDE in various matrices • Investigations on the possibility of migration from different types of polymers.

144 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2. 1 Identity

Chemical structure:

6' 6 0 5

4' 4

Drs

Chemical formula: C12H2Br80 Relative molecular mass: 801.47 Common names: octabromodiphenyl ether (OBDE) octabromodiphenyl oxide CAS registry number: 32536-52-0 EINECS number: 2510879 MITI number: 3-3716 CAS name: 1, 1'-oxy(bis)­ octabromo-benzene Synonyms: octabromodiphenyl ether; benzene, 1, 1'-oxy-bis-,octabromo-phenyl ether

Based on the chemical structure, there are 12 possible isomers of octabromodiphenyl ether. From: IRPTC (1988); US EPA (1984); Ethyl Corp. (1992b).

145 EHC 162: Brominated diphenyl ethers

2.1.1 Technical product

Trade names: Bromkal 79-8 DE; DE-79TII; FR 143; Tardex 80; FR 1208; Adine 404; Saytex 111

The commercial product is a mixture of polybrominated diphenyl ethers with the following typical composition (see Table 1):

0-0.7% decabromodiphenyl ether 9.5-11.3% nonabromodiphenyl ether 31.3-35.3% octabromodiphenyl ether 43.7-44.5% heptabromodiphenyl ether 10.5-12.0% hexabromo- and pentabromodiphenyl ether.

Commercial OBDE has also been reported to be a mixture of 4% hexabromo-, 62% hepta-, and 34% octabromodiphenyl ether (De Kok et al., 1979).

2.2 Physical and chemical properties

Commercial products based on OBDE are off-white powders with a faint odour, and a bromine content of 79-81 % . In case of fire, and, in the presence of fuels, hydrogen bromide and/or bromine may be liberated (Kopp, 1990).

Melting point: 200 (167-257) °C, Ethyl Corp. (1992b); 79-87 oc; 75-125 °C, Kopp (1990); and 170-220 °C, De Kok et al. (1979) Vapour pressure: < 10-7 mmHg at 25 oc

146 Octabromodiphenyl ether

Solubility at 25 oc in g/litre:

water < 1 methanol 2 (7) methylene chloride 110 toluene 190 (353) benzene 200 styrene 250 methyl ethyl ketone 40 acetone 20 (122)

(From: Great Lakes Chemical Corporation, 1987, 1990a)

Specific gravity: 2.76 (2.63)

(From: US EPA, 1989, 1986)

n-Octanol!water partition coefficient (log Pow): 5.5; 8.35-8.90

(From: Watanabe & Tatsukawa, 1990; Ethyl Corporation, 1992b).

2.3 Analytical methods

No specific data are available (see General Introduction section 2.1 and Table 2).

147 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

Octabromodiphenyl ether has not been reported to occur naturally (see General Introduction, section 1.1).

3.2 Anthropogenic sources

3. 2. 1 Production levels and processes

Octabromodiphenyl ether is synthesized by treating diphenyl ether with 8 equivalents of Br2 in the presence of Al 2Cl 6/Al 2Br6, first at 35 oc and then at 120 oc (US EPA, 1986). No data are available on production levels. The annual consumption of OBDE in Japan was 150 tonnes in 1983, and 1000 tonnes in 1987, main! y used in the preparation of ABS (Watanabe, 1987; Watanabe et a!., 1987b). Consumption in Germany was 600-800 tonnes/year in plastics in 1988 (CEM, 1989). Estimation of total use of octabromodiphenyl ether in the Netherlands in 1988 was 600-800 tonnes. The actual worldwide consumption of OBDE per year is 6000 tonnes (Arias, 1992).

3.2.2 Uses

The high bromine content and its broad melting range make OBDE the material of choice for a large variety of thermoplastics. Its use is recommended for injection mouldings, especially when high surface quality is desirable. Applications: ABS, nylon, high impact polystyrene, low density polyethylene, polypropylene random copolymer (Flick, 1986). It is also used in adhesives and coatings. The major use of OBDE is in computer and business equipment cabinets (Personal communication, McAllister).

148 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

4.1 Biotransformation

No data are available.

4.2 Abiotic degradation

4. 2. 1 Pyrolysis of octabromodiphenyl ether

Pyrolysis of octabromodiphenyl ether (OBDE) at 630 °C, in air, resulted in approximately 96% decomposition leading to the formation of polybrominated benzenes (PBBz) and about 5% of PBDF and PBDD, mainly two pentabromodibenzodioxins and a hexabromodibenzofuran. Small amounts of tri- to heptabromo­ dibenzodioxins and tetra- to heptabromodibenzofurans were present (Buser, 1986).

4.2.2 Pyrolysis studies with polymers containing octabromodiphenyl ether

Pyrolysis studies were conducted on ABS contammg OBDE (15%) and antimony trioxide (6%) at 600 oc (Neupert et a!., 1989). Brominated dibenzofurans and brominated dibenzodioxins were identified in the pyrolysis residues, however, the brominated dibenzodioxins and 2,3,7,8-TeBDF were present in very low quantities. The pyrolysis of Cycolac, flame retarded with OBDE in com­ bination with antimony trioxide, gave high levels of brominated dibenzodioxins and dibenzofurans and significant levels (9.3 mg/kg) of 2,3,7,8-isomers at 600 oc. Pyrolysis temperatures were 200, 250, and 600 oc during 30 min. The total PBDF were 110.8, 666, and 1631 mg/kg, respectively. The values for PBDD were 1.75, 0.75, and 31.5 mg/kg, respectively (Fresenius Institute, 1990).

149 EHC 162: Brominated dipheny/ ethers

4.2.3 Behaviour of octabromodipheny/ ether during processing

BFRIP designed an experiment to investigate the behaviour of OBDE in ABS under controlled moulding or extrusion conditions. The polymer system ABS/OBDE was operated under different conditions (Table 25). After moulding, all the samples were analysed for brominated dibenzodioxins and dibenzofurans. With the exception of a single sample, brominated dibenzodioxins were not identified in any of the samples. In this sample, the 2,3, 7,8- brominated dibenzofurans were seen only at very low concen­ trations (Table 26). The data show that processing of the resin systems under normal conditions (225 oc; 1-min cycle) resulted in no change in composition from that of the base resin formulation (BFRIP, 1990; McAllister et al., 1990).

Table 25. Moulding study w1th ABS/OBDE system at different processmg temperatures..

Polymer/FR Seventy Conditions

ABS/OBDE normal 225 °C, 1 mm cycle abus1ve 245 °C, 10 mm cycle

ABS/OBDE acrylonitrile-butadiene-styrene/ 79.8% OBDE + 16.0% antimony trioxide 4.2%

8 From: McAllister et al. (1990).

Craig et al. (1989) measured the PBDF and PBDD contents of pre- and post-extruded Cycolac resin treated with OBDE and antimony trioxide. Two samples were tested at extrusion temperatures around 220 oc. PBDF levels varied from one another by a factor of 4 in the pre-extn.sion samples and by a factor of 2 in the post-extrusion samples. The higher levels of total PBDF were 38 300 /-tg/kg in the pre-extruded and 84 500 /-tg/kg in the post-extruded resins. PBDD was not detected in the pre­ extruded resin, but, in one post-extruded sample, it was found at a level of 112 /-tg/kg. The fumes emitted during extrusion were also analysed and a level of 1850 /-tg/kg was found. PBDD was found in a concentration of 0.54 /-tg/kg. (Fume data expressed as /-tg/kg of extruded resin).

150 Octabromodiphenyl ether

Table 26. Comparison of Triangle Laboratories Inc. (TLI) (Research Triangle Park) and US EPA Laboratory (Las Vegas) results on moulded polymer samples contammg various flame retardants. (All concentrations are in mg/kg)8

ABS with octabromodiphenyl ether

Normal 1222·16-4 Abusive 1 222-1 6-5

Compound TLI us TLI us EPAC EPA

1,2,3,7,8-PeBDD < 0.002 0.02

2,3,7,8-TeBDF < 0.002 0.004

Total TeBDD < 0.001 0.01

Total PeBDD 0.03 < 0.13

Total TeBDF 0.003 0.003 0.17 0.16

Total PeBDF 1.1 1.3 < 14.0 31.5

Total HxBDF < 135.0 2.2 < 118.0 9.1

Total HpBDFb < 6.6 0.6 < 2.9 0.7

Total OBDFb < 34.5 0.04 < 13.9 0.02

8 From: BFRIP (1990). Values preceded by< are max1mum poss1ble. Analytical signals met 1dent1f1cation critena, but may inciude contribution from Interferences. US EPA and TLI used different 1dent1f1cat1on cntena resulting in differences in reported values. bConcentrat1on of HpBDF and OBDF from TLI are not validated because of lack of standards. Concentrations are reported for companson only. cAverage of two analys1s of same sample.

4.3 Bioaccumulation

A single study on a mixture of PBDE including HxBDE to DeBDE indicated little bioaccumulation in carp with a bio­ concentration factor of < 4 after 8 weeks of exposure (CBC, 1982).

4.4 Ultimate fate following use

For the ultimate fate of OBDE in the environment see General Introduction, section 6.1.

151 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

5.1 Environmental levels

5.1.1 Water

In Japan, OBDE was not detected in 75 water samples (limit of determination 0.1 ~-tg/litre) in 1987 and was not detected in 147 water samples collected at 49 areas (limit of determination, 0.07 ~-tg/litre) in 1988-89 (Environment Agency Japan, 1989, 1991).

5. 1.2 Aquatic sediments

In 1987, environmental surveys were conducted concerning OBDE in bottom sediment. OBDE was detected in 3 out of 51 samples at concentrations ranging from 8 to 21 ~-tg/kg in 1987 (limit of determination 7 ~-tg/kg dry weight) and was detected in 3 out of 135 samples, collected at 45 areas, at concentrations ranging from 15 to 22 ~-tg/kg dry weight (limit of determination 5 ~-tg/kg) in 1988-89 (Environment Agency Japan, 1989, 1991).

5. 1.3 Aquatic and terrestrial organisms

In Japan, OBDE was not detected in 75 fish samples in 1987 and was not found in 144 fish samples collected in 48 areas in 1988-89 (limit of determination 5 ~tglkg wet weight) (Environment" Agency Japan, 1989, 1991).

5.2 Exposure of the general population

In the USA, Cramer et a!. (1990a,b) studied the presence of PBDD/PBDF in human adipose tissue samples of the fiscal year 1987 (National Human Adipose Tissue Survey). The samples were derived from 865 specimen combined to form 48 composite analogues. The composite design was based on 9 census divisions and 3 age groups. The analysis was carried out using HRGC/HRMS to determine PBDD/PBDF. No PBDF/PBDD was

152 Octabromodiphenyl ether

found (limits of determination, 10-40 ng/kg, depending on congeners). Identification of the PBDE was based on comparison of full scan mass spectra of the samples with the available standards, application of SIM techniques to compare theoretical ion ratios with observed ion ratios for characteristic ions, and measurement of fragment losses from the molecular ion clusters. Preliminary evidence for the presence of OBDE was found (frequency, 60%) with an estimated concentration range of ND- 8000 ng OBDE/kg (Cramer et al., 1990a,b; Stanley et al., 1991).

5.3 Occupational exposure during manufacture, formulation, or use

No data are available.

153 6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS

6. 1 Single exposure

6. 1. 1 Oral: Rat

The acute oral LD50 in the rat is > 28 g/kg body weight (Kalk, 1982); > 5 g/kg body weight (Kopp, 1990; Great Lakes Chemical Corporation, 1990a). Male Charles River CD rats were administered commercial OBDE, suspended in corn oil, by intubation, at doses of 50, 500, or 5000 mg/kg body weight. The observation period was 14 days. The rats showed normal weight gain and no animals died (Great Lakes Chern Corp., 1987; 1990a).

6.1.2 Dermal: Rabbit

Commercial OBDE was applied to the clipped, abraded, or intact skin of male and female albino rabbits at concentrations of 200 or 2000 mg/kg body weight for 24 h. During the observation period of 14 days, none of the rabbits died and all had normal

weight gain. The dermal LD50 for rabbits is > 2 g/kg body weight (Great Lakes Chemical Corporation, 1987, 1990a).

6. 1.3 Inhalation: Rat

The inhalation LC50 of Saytex 111 in rats was > 50 mg/litre (US EPA, 1986). Male and female Charles River CD nts were exposed for 1 h to concentrations of commercial OBDE in air of 2 or 60 mg/litre. The physical nature of the substance precluded administration at higher levels than 60 mgllitre. Rats exposed to 2 and 60 mg/litre had decreased motor activity, erythema, and eye squint, during exposure. The animals exposed to 60 mg/litre also had tachypnea. During the 14-day observation period, the animals appeared normal, and exhibited normal body weight gain, except for one rat at the highest dose level, which showed salivation on days 5 and 7

154 Octabromodiphenyl ether

of the observation period (Great Lakes Chemical Corporation, 1987) (no further details).

6.2 Short-term exposure

S. 2. 1 Oral: Rat

Charles River CD rats were fed commercial OBDE at daily, dietary dose levels of 0, 100, or 1000 mg/kg for 28 days. There were 10 male and 10 female rats in each dose group. No changes in appearance, behaviour, mortality, feed consumption, or body weight gain were observed. Results of haematology, blood chemistry, and urinalysis were similar to those in the controls. Absolute and relative liver weights were significantly increased in female rats given 100 mg/kg and in rats of both sexes given 1000 mg/kg diet. Other increases in organ weights were not considered compound-related. No gross pathological lesions were noted in rats in any of the groups. Compound-related histopatho­ logical liver lesions were observed in both treated groups of rats. They consisted of enlarged centrolobular and midzonal liver parenchymal cells in which the cytoplasm had large areas of finely granular structures containing eosinophilic "round bodies". These changes occurred more frequently and with greater severity in the male animals. Their incidence and severity were dose-related. Rats given 1000 mg/kg had a slight to moderate hyperplasia of the thyroid, but it was not clear whether this was compound-related. Dose-related increases in total bromine levels of the liver were noted in both males and females and ranged from about 6 to 137 times the levels found in controls (Great Lakes Chemical Corporation, 1987). Another 28-day feeding study was carried out on 10 male and 10 female Charles River CD rats per group, which were administered a diet containing 100, 1000, or 10 000 mg commercial OBDE/kg. The control group consisted of 35 male and 35 female rats from the 90-day feeding study, described below. At the end of the study, 5 rats of each sex/group were sacrificed and the remaining 5 animals/sex per group were maintained on normal diets for 4 weeks (recovery period). No changes in appearance, behaviour, or mortality were observed. Food consumption and body weight gain were slightly higher in

155 EHC 162: Brominated diphenylethers

the control group. Haematology values were normal, but serum urea nitrogen levels were slightly elevated in some of the rats given 10 000 mg/kg diet. An increase in absolute and relative liver weights was observed in some of the rats given 1000 and 10 000 mg/kg. At necropsy, the livers of some animals in the 10 000 mg/kg group showed accentuated lobulization and discoloration. The livers of rats from all 3 dose levels showed enlargement of the centrolobular and midzonal hepatocytes, the cytoplasm of which had large areas of finely granular appearance and frequently contained eosinophilic "round bodies". In the 10 000 mg/kg group, vacuolization of hepatocytes and necrosis of scattered individual hepatocytes were seen. In all 3 treated groups, the liver lesions were less severe after the 4-week recovery period than during the administration of the compound. A dose-related increase in liver total bromine content was seen in rats in all treated groups after 4 weeks of treatment, but these total bromine levels decreased rapidly in the recovery period. Only in the rats receiving the lowest dose level did the liver total bromine concentration approach control levels after a 4-week withdrawal period (Great Lakes Chemical Corporation, 1987). Charles River CD rats were fed commercial OBDE at dietary levels of 0, 100, 1000, or 10 000 mg/kg for up to 13 weeks. There were 35 male and 35 female rats in each dose group. Behaviour, appearance, body weight, food consumption, haematology, blood chemistry, and urinalysis were studied after 1 and 2 months, and, at the end of the study, in groups of 5 rats/sex per group. The remaining 20 rats per group were used to study the recovery and 5 rats/sex per group were sacrificed after 13 and 21 weeks and 6 months after withdrawal. During the study, a few rats out of each group died, but without any dose-relationship, the majority of these deaths occurring after the collection of blood. In the 100 mg/kg diet group, the only effect that was seen was an increase in absolute and relative liver weights. Microscopic changes were seen in 4 out of 10 rats, and were typified by granular cytoplasmic changes. Liver total bromine contents increased during the 13-week treatment, but decreased during the recovery period. In the 1000 mg/kg group, a decrease in body weight gain was observed, but haematology, blood chemistry, and urinalysis results

156 Octabromodiphenyl ether

were comparable with the controls. Increases in absolute and relative liver and thyroid weights were observed, but these effects were not seen in the animals sacrificed during the recovery period. Microscopic lesions were seen in the cytoplasm of the centrolobular and midzonal hepatocytes and included vacuolization, and hyaline intracytoplasmic inclusions. A hyperplastic nodule was found, after 6 months withdrawal, in one rat each from the 1000 and 10 000 mg/kg groups. In the 10 000 mg/kg group, a decrease in body weight gain was observed, even during the withdrawal period. Decreases in haemoglobin, haematocrit, and erythrocyte counts were also observed. One female animal had hypochromia, polychromia, and anisocytosis of the erythrocytes. Glucose levels in the blood were slightly lower than in the controls. Orange colouration of the urine was observed during weeks 13-39. A significant increase in absolute and relative liver, kidney, and thyroid weights was observed. At autopsy, there was accentuated lobulation and yellowish mottling of the livers and brownish discoloration of the liver and kidneys. After one year of recovery, no such gross changes were observed. Histopathologically, the liver changes consisted of granular cytoplasmic changes, cytoplasmic vacuolization (possibly representing fatty degeneration), necrosis of scattered parenchymal cells or of centrolobular cells, centrolobular fibrosis, and pigmented Kupfer cells. In the kidneys, the changes were characterized by the occurrence of small to moderate numbers of cortical regenerative tubules. One rat had a severe tubular nephrosis. Cellular changes in the thyroid were probably compound-related. During the recovery period, the histological changes decreased in severity and frequency. The total bromine content of the liver increased during the 13 weeks of treatment and decreased during the recovery period, but remained higher (not significantly) than the control values after one year (Great Lakes Chemical Corporation, 1987).

6. 2. 2 Inhalation: Rat

Charles River CD rats were exposed (whole-body) to a micronized dust of commercial OBDE, introduced into inhalation chambers at nominal concentrations of 1.2, 12, 120, and 1200 mg/m3 for 8 h/day on 14 consecutive days. Actual airborne

157 EHC 162: Brominated diphenyl ethers

dust concentrations were 15-45% of the nominal values. It was not possible to measure the extent of oral intake of the substance. There were 5 male and 5 female rats in each dose group and in the controls. No animals died during the test period nor were there any changes in appearance or general behaviour in the 1.2 and 12 mg/m3 groups. By the end of the 8-h exposure period, all animals in the 1200 mg/m3 group and part of the 120 mg/m3 group exhibited a fast breathing pattern, which had disappeared by the morning following exposure. Food consumption, body weight gain, haematology, blood chemistry, and urinalysis in all of the dose groups were normal. The total bromine concentrations in the lung, liver, and fat were significantly higher than in the controls. At autopsy, the average total bromine concentrations in the lung and fat were about 1.5-12.5 times higher than in the liver. The relative liver weights of the animals in the 12, 120, and 1200 mg/m3 dose groups were significantly increased in a dose­ related manner. These changes were accompanied by histopathological lesions cons1stmg of focal to multifocal cytoplasmic enlargement of the hepatocytes, and focal acidophilic degeneration of individual, and small groups of, liver cells. At the 2 highest dose levels, the enlargement of the hepatocytes was multifocal to diffuse in distribution and small to large areas had necrosis in the centrolobular regions of the affected liver lobules, especially in the 1200 mg/m3 group. No other compound-related effects were observed (Great Lakes Chemical Corporation, 1987).

6.3 Long-term exposure

No data are available.

6.4 Skin and eye irritation; sensitization

6.4. 1 Skin irritation

Commercial OBDE was applied to the clipped and occluded intact, or abraded, skin of male and female albino rabbits at a dose of 500 mg. After 24 h, the skin was washed and examined for irritation. The examination was repeated after 72 h. One rabbit had slight erythema at 72 h; the remaining rabbits did not have

158 Octabromodiphenyl ether

skin changes. It was concluded that OBDE is not a primary skin irritant (Great Lakes Chemical Corporation, 1987).

6.4.2 Eye irritation

Single applications of 100 mg commercial OBDE were made into the conjunctival sac of the eye of 3 male and 3 female New Zealand white rabbits. Examinations were made at 24, 48, and 72 h, and 7 days. A slight discharge was noted from the eyes of 2 rabbits at 24 h and a slight redness was noted in the eye of one rabbit at 48 h. No ocular irritation or corneal damage (sodium fluorescein and UVR were used) was observed (Great Lakes Chemical Corporation, 1987).

6.5 Teratogenicity, reproductive toxicity, and embryotoxicity

6. 5. 1 Teratogenicity

6. 5. 1. 1 Oral: Rat

In a range-finding study, female rats (number not specified) were dosed daily, by gavage, from days 6 to 15 of gestation with 2.5, 10.0, 15.0, 25.0, or 50.0 mg commercial OBDE (DE-79)/kg body weight. All animals survived until gestation day 20, when they were sacrificed. At 25.0 mg/kg, increased serum bromine levels were observed. Mean maternal body weight gain was reduced in the 50.0 mg/kg group during gestation. Increased numbers of late resorptions and significantly reduced mean fetal weights were observed at the highest dose level. The cholesterol level was slightly increased in the dams given 50.0 mg/kg. No compound-related microscopic findings were observed in the liver and kidneys of the mothers. No compound-related effects were observed at 15.0 mg/kg or lower. The malformations and developmental variations observed in the 50.0 mg/kg group were associated with maternal toxicity. Fetal anasarca and bent limb bones were observed at this dose level. Mean fetal body weight and increased post implantation loss due to late resorptions was also observed at this level, but the losses were not statistically significant, compared with the controls. Reduced ossification of the skull. various unossified bones, and two instances of bent ribs

159 EHC 162: Brominated diphenyl ethers

were noted at this dose level, and were probably secondary to maternal toxicity (Great Lakes Chemical Corporation, 1987) (abstract). Four groups of 25 pregnant Charles-River Crb:COBS CD (SD) BR rats were administered corn-oil suspensions of Saytex 111, by gavage, at doses of 0, 2.5, 10.0, or 25 mg/kg body weight per day on days 6-15 of gestation. The dams were sacrificed on day 20 of gestation and the fetuses were examined for gross visceral and skeletal abnormalities. The substance was more toxic to the conceptus than to the dam. At 25.0 mg/kg, dose-dependant effects on the conceptus were observed. These included reduced average fetal body weight, increased embryo/fetal deaths (resorptions), fetal malformations, such as enlarged heart, rear limb malformation, and delayed skeletal ossification. At 10 mg/kg, the only observed effect was a statistically insignificant reduction in average fetal body weight (US EPA, 1986).

6. 5. 1. 2 Oral: Rabbit

Groups of 26 inseminated adult New Zealand White rabbits (weight 3.5-4.5 kg) were treated with 0 (corn oil), 2.0, 5.0, or 15 mg Saytex 111/kg body weight per day, by gavage, on days 7-19 of gestation. Saytex 111 was a mixture containing; 0.2% PeBDE, 8.6% HxBDE, 45.0% HpBDE, 33.5% OBDE, 11.2% NBDE, and 1.4% DeBDE. Body weight gain was recorded on gestation days 0, 7, 10, 13, 16, 20, and 28. In addition, maternal liver, kidneys, and gravid uterine weights were measured at the time of hysterectomy. The offspring were examined on day 28 of gestation. A statistically significant increase in liver weight and a decrease in body weight gain were observed in the 15 mg/kg group. There was no statistically significant deviation in maternal mortality, number of pregnancies, number of litters with viable pups, corpora lutea/dam, implantations/dam, live fetuses/litter, percentage of resorptions, and fetal body weight. Slight fetal toxicity was observed in the 15 mg/kg group, as evidenced by a significant increase in delayed ossification of the sternebrae. There was an increase in the incidence of retrocaval ureter in the 5 and 15 mg/kg group and fused sternebrae in the 5 mg/kg group. These increases were not dose related. It was concluded by the authors

160 Octabromodiphenyl ether

that there was no evidence for teratogenic activity but that there was slight fetotoxicity at maternally toxic dose levels, e.g., 15 mg/kg body weight (Breslin eta!., 1989).

6.6 Mutagenicity and related end-points

6. 6. 1 DNA damage

An unscheduled DNA synthesis (UDS) assay, a test to induce DNA damage followed by repair in mammalian cells, was carried out with monolayers of WI-38 human fibroblast cells, which were exposed to commercial OBDE in the presence of radiolabelled thymidine. OBDE was tested at 5 concentrations ranging from 60 to 300 ~-tg/ml. UDS was not induced by OBDE either in the presence or in the absence of a metabolic activation system (Great Lakes Chemical Corporation, 1987).

6. 6. 2 Mutation

Commercial OBDE was examined for mutagenic activity at a number of concentrations in in vitro microbial assays using Salmonella typhimurium and Saccharomyces cerevisiae with, and without, liver microsomal enzyme preparations from Aroclor­ induced rats. The results of these tests were all negative (Great Lakes Chemical Corporation, 1987) (no details).

6. 6. 3 Chromosomal effects

In an assay for sister chromatid exchanges, Chinese hamster ovary cells were exposed to concentrations of commercial OBDE of 7.5, 25, 75, 250, or 750 ~-tg/ml (in DMSO), for 2 h, in the presence, or absence, of a metabolic activation system. The exposure period was followed by a 24-h expression period. No statistically significant increases in the number of exchanges per chromosome or the number of exchanges per cell were seen at any of the levels tested (Great Lakes Chemical Corporation, 1987).

6.7 Carcinogenicity

No data are available.

161 EHC 162: Brominated diphenyl ethers

6.8 Other special studies

6.8.1 Liver

Commercial OBDE in corn oil was administered by gavage to six male Sprague-Dawley rats (200-250 g) for 90 days. When extensive induction was revealed at all the original doses of 6.25, 12.5, and 25 ~-tmol/kg per day, the study was repeated at doses of 0.78, 1.56, and 3.13 ~-tmol/kg per day. OBDE did not cause induction of NADPH cytochrome c reductase and cytochrome P450 at the lower doses. However, a dose of 0.78 ~-tmol/kg per day caused increases in both 0-ethyl-0-p-nitrophenyl phenyl­ phosphonothioate (EPN) detoxification and p-nitroanisole demethylation; larger increases were seen with increasing dose levels. After a 30-day recovery period, evidence of the maintenance of an induced state was seen only in animals receiving 3.13 ~-tmol/kg per day. These elevations were still observable 60 days after the last dose. No histological liver abnormalities were observed in rats treated with 3.13 ~-tmollkg body weight or less (Carlson, 1980b). In another study on male rats (200-250 g) administered commercial OBDE, by gavage, at 0.1 mmollkg per day in corn oil for 14 days, the above increase in enzyme activity was accompanied by an increase in activity of UDP-glucuronyl transferase and benzo[a]pyrene hydroxylase 24 h after the seventh dose (Carlson, 1980a). Measurements made on days 30 and 60 of recovery after 90 days exposure showed that the indicators of induced xenobiotic metabolism returned slowly to control values. Koster et a!. (1980) found a strong porphyrinogenic effect in cultures of chick embryo liver cells at concentrations of 10 llg commercial OBDE (in DMSO)/ml medium, with, and without, pretreatment of j)-napthoflavone, an inducer of P450, P448, and delta-aminolevulinic acid synthethase. The effect was determined semiquantitatively with fluorescence microscopy, 24 h after addition of the flame retardant.

162 Octabromodiphenylether

6.9 Appraisal

In 28-day and 90-day rat studies, 100 mg OBDE per kg diet (equivalent to 5 mg/kg body weight) induced minimal effects in the liver. No no-effect level was established. In a 14-day inhalation study with micronized dust of OBDE, no effects were found with 3 exposure to 12 mg/m . Teratogenicity studies showed a no-effect level of 2.5 mg/kg body weight. At the highest reported value of OBDE of 8000 ng/kg, from the Human Adipose Tissue Sample Study, assuming 15% adipose tissue in the adult male, a "stored" dose of 1.2 J.tg/kg can be calculated. Assuming 1% of the administered dose was absorbed, this would extrapolate to a total dose of 120 J.tg/kg. With the further assumption that the total exposure occurred over one year, a daily dose of 0.38 J.tglkg per day can be calculated. This dose is approximately 4 orders of magnitude below the most sensitive end­ point in mammalian toxicity testing on OBDE (NOEL = 2.5 mg/kg body weight in a teratology study).

163

HEPT ABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

Heptabromodiphenyl ether is not manufactured or used. There is no database on pure HpBDE on which to make an evaluation. No data are available on the following topics:

• Kinetics and metabolism in laboratory animals and humans • Effects on humans • Effects on other organisms in the laboratory and field • Previous evaluations by international bodies.

Because HpBDE is the major component of commercial octabromodiphenyl ether, the summary, evaluation, conclusions, and recommendations on commercial OBDE, are relevant to "commercial" HpBDE.

167 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, AND ANALYTICAL METHODS

2.1 Identity

Chemical structure:

6 6'

5

4

Chemical formula: Relative molecular mass: 722.3 CAS registry number: 68928-80-3 CAS name: 1, 1'-oxy-bis(heptabromobenzene) Common name: heptabromodiphenyl ether (HpBDE)

From: US EPA (1986).

On the basis of the chemical structure, there are 24 possible isomers of heptabromodiphenyl ether.

2.2 Physical and chemical properties

Melting point: 70-150 oc (decomposition > 232 °C) Density: 2.6 at 20 oc

168 Octabromodiphenyl ether

Vapour pressure: < 13.3 Pa at 20 oc n-Octanol!water partition coefficient (log pow): not available

From: US EPA (1986).

2.3 Analytical methods

No specific data are available (See General Introduction, section 2.1 and Table 2).

169 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

Heptabromodiphenyl ether has not been reported to occur naturally (see General Introduction, section 1.1).

3.2 Anthropogenic sources

3. 2. 1 Production levels and processes

Heptabromodiphenyl ether is not produced commercially or used, but octabromodiphenyl ether contains approximately 44% HpBDE (see General Introduction, Table 1).

170 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

A single study on mixed PBDE ranging from HxBDE and DeBDE indicated little bioaccumulation in carp with a bioconcentration factor of < 4, after 8 weeks of exposure (CBC, 1982).

171 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

Cramer et al. (1990a,b) studied the presence of PBDD/PBDF in human adipose tissue samples in the USA in the fiscal year 1987 (National Human Adipose Tissue Survey). The samples were derived from 865 specimens combined to form 48 composite analogues. The composite design was based on 9 census divisions and 3 age groups. The analysis was carried out using HRGC/HRMS to determine PBDD/PBDF. No PBDF/PBDD were found, the limit of determination ranging from 10 to 40 ng/kg, depending on the congeners. Identification of the PBDE was based on comparison of full scan mass spectra of the samples with the available standards, the application of SIM techniques to compare theoretical ion ratios with observed ion ratios for characteristic ions, and the measurement of fragment losses from the molecular ion clusters. Preliminary evidence for the presence of heptabromodiphenyl ether was found at a frequency of 100%, with an estimated concentration range of 1-2000 ng HpBDE/kg (Cramer et al., 1990a,b; Stanley et al., 1991).

172 6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS

No data are available on the following topics:

• Short-term exposure • Long-term exposure • Reproductive toxicity, embryotoxicity, and teratogenicity • Mutagenicity • Carcinogenicity. 6.1 Single exposure

The acute oral LD50 for the rat is > 5 g/kg and the dermal

LD50 for the rabbit, > 2 g/kg body weight (Kopp, 1990).

6.2 Skin and eye irritation; sensitization

The substance is not irritant for either the skin or eyes (Kopp, 1990).

173

HEXABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

Hexabromodiphenyl ether is not manufactured or used, but occurs as a contaminant of commercial brominated diphenyl ethers. Such levels of hexabromodiphenyl ether should be minimized to avoid contamination of the environment and exposure of humans. There is no database on which to make an evaluation. No data are available on the following topics:

• Effects on laboratory mammals and in vitro test systems • Effects on humans • Effects on other organisms in the laboratory and field • Previous evaluations by international bodies.

177 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2.1 Identity

Chemical structure:

6' 6

5

4' 4

Chemical formula: Relative molecular mass: 643.62 CAS registry number: 36483-60-0 CAS name: 1.1'-oxy-bis-hexabromobenzene Common names: hexabromodiphenyl ether (HxBDE) hexabromodiphenyl oxide

From: (US EPA, 1984, 1986).

On the basis of the chemical structure, there are of 42 possible isomers of hexabromodiphenyl ether.

2. 1.1 Technical product

Trade names: BR 33N

178 Heptabromodiphenyl ether

2.2 Physical and chemical properties

Vapour pressure: 0.95-0.99 kPa at 25 oc n-Octanol/water partition coefficient (log Pow): 6.86-7.92

From: Pijnenburg & Everts (1991).

2.3 Analytical methods

No specific data are available (see General Introduction, section 2.1 and Table 2).

179 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

Hexabromodiphenyl ether has not been reported to occur naturally (see General Introduction, section 1.1).

3.2 Anthropogenic sources

As far as is known, hexabromodiphenyl ether has not been produced commercially or used, but it is a component of TeBDE, PeBDE, and OBDE at concentrations ranging from 4 to 12% (see General Introduction, Table 1).

3.3 Uses

Total use of penta- and hexabromodiphenyl ethers in the Netherlands in 1988 was estimated to be 350 tonnes (Anon, 1989).

180 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

A single study on a mixture of PBDE, ranging between HxBDE and DeBDE, indicated little bioaccumulation in carp with a bioconcentration factor of < 4, after 8 weeks of exposure (CBC, 1982).

181 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

5.1 Levels in the environment

5.1.1 Water

In Japan, HxBDE was not detected in 75 samples of water in 1987 or in 150 samples collected in 50 areas in 1988-89 (in both cases the limit of determination was 0.04 ~-tgllitre) (Environment Agency Japan, 1989, 1991).

5. 1. 2 Aquatic sediments

Marine, estuarine, and river sediment samples were collected at different places in Japan in 1981-83 and analysed for HxBDE. Five out of 15 samples contained 9-26 ~tglkg (Watanabe, 1987; Watanabe eta!., 1987b). In 1987, environmental surveys were conducted on HxBDE levels in sediment in Japan. HxBDE was detected in 4 out of 69 samples at concentrations ranging from 7 to 77 ~-tg/kg dry weight (limit of determination 5 .I ~tglkg dry weight) in 1987, and, in 4 out of 141 samples collected in 47 areas in 1988-89, at concentrations ranging from 4.5 to 18 ~-tg/kg dry weight (limit of determination 3.5 ~tglkg dry weight) (Environment Agency Japan, 1989, 1991).

5. 1.3 Aquatic and terrestrial organisms

Mussel and a few species of fish (mullet, goby, and Japanese sea bass) were collected from different seashores in Japan from 1981 to 1985. Other fish species were purchased at a wholesale commercial source in Osaka Prefecture in 1981. HxBDE could not be detected ( < 0.2 ~tglkg wet weight) in any of the 5 mussel samples or in the 12 fish samples (Watanabe, 1987; Watanabe et a!., 1987b). In 1987, environmental surveys were conducted on HxBDE levels in fish in Japan. HxBDE was detected in 5 out of 75 fish

182 Heptabromodipheny/ ether

samples at concentrations ranging from 3.8 to 14 JLglkg wet weight in 1987 and was detected in 5 out of 144 samples collected at 48 areas at concentrations ranging from 2 to 6 JLg/kg wet weight in 1988-89 (limit of determination 2 JLg/kg wet weight) (Environ. Agency Japan, 1989, 1991).

5.2 General population exposure

In the USA, Cramer et al. (1990a,b) studied the levels of PBDD/PBDF in human adipose tissue samples in 1987 (National Human Adipose Tissue Survey). The samples were derived from 865 specimens combined to form 48 composite analogues. The composite design was based on 9 census divisions and 3 age groups. The analysis was carried out using HRGC/HRMS to determine PBDD/PBDF. No PBDF/PBDD were found, the limit of determination ranging from 10 to 40 ng/kg, depending on the congeners. Identification of the PBDE was based on comparison of full scan mass spectra of the samples with the available standards, application of SIM techniques to compare theoretical ion ratios with observed ion ratios, for characteristic ions, and measurement of fragment losses from the molecular ion clusters. Preliminary evidence for the presence of HxBDE was found at a frequency of 72%, in an estimated concentration range of ND to 1000 ng HxBDE/kg (Cramer et al., 1990a,b; Stanley et al., 1991).

183 6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

The half-life of pentabromodiphenyl ether (Bromkal 70) was investigated in the perirenal fat of groups of 3 male and 3 female Wistar rats (weight 160-180 g), following a single oral dose of 300 mg/kg body weight in peanut oil. The groups were killed on days 1, 2, 3, 4, and 7 and then weekly for 10 weeks. Perirenal fat was collected and analysed. Half-lives in male and female rats of 2 hexabromodiphenyl ethers (HxBDE(1) and HxBDE(2)) were: for female rats, 44.6 (37 .4-51.9) days and 90.0 (78. 7-103.6) days, and, for male rats, 55.1 (48.4-61.7) and 119.1 (102.8-136.1) days, respectively (Von Meyerinck et al., 1990).

184 PENTABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

Pentabromodiphenyl ether is not manufactured or used. No data are available on the following topics:

• Effects on humans • Effects on other organisms in the laboratory and field • Previous evaluations by other international bodies. 1.1 Summary and evaluation

1. 1. 1 Identity, physical and chemical properties

Commercial pentabromodiphenyl ether (PeBDE) is a mixture of tetra-, penta-, and hexabromodiphenyl ethers. It contains approximately 50-60% PeBDE and 24-38% TeBDE. On the basis of the chemical structure, there are 46 possible isomers of PeBDE and 42 possible isomers of TeBDE. The commercial products seem to contain 3 main components, i.e., 2,2' ,4,4' ,5-PeBDE, 2,2',4,4'-TeBDE, and an unidentified congener containing 5 bromines. The melting point is -7 to -3 oc and the boiling point, above 200 °C. The vapour pressure is low: < 10·7 mmHg and the solubility in water is negligible. The n-octanol/ water partition coefficient (log Pow) > 6.

1. 1.2 Production and uses

PeBDE is used as an additive in epoxy resins, phenol resins, polyesters and polyurethane, and textiles. Worldwide consumption is approximately 4000 tonnes per year. It is one of the major commercial brominated diphenyl ether flame retardants.

1. 1.3 Environmental transport, distribution, and transformation

Components of commercial PeBDE have been found in biota, sediment. and sewage sludge samples. Commercial PeBDE

187 EHC 162: Brominated diphenylethers

components are likely to be persistent and bioaccumulate. A bioconcentration factor of over 10 000 has been found in carp for PeBDE. Pyrolysis studies with commercial PeBDE showed that PBDF and PBDD are formed. The optimal temperature for the formation of the PBDF and PBDD was between 700-800 °C. When PeBDE was pyrolysed in the absence of oxygen, polybromobenzenes, polybromophenols, and PBDF were formed.

1.1.4 Environmental levels and human exposure

Sediment samples taken from rivers and estuaries in Japan showed levels ranging from no PeBDE ( < 2 ~-tg/kg) up to 28 ~-tg/ kg dry weight. In Sweden, the concentrations in sediment samples of certain rivers were up to 1200 1-tg 2,2',4,4,'5-PeBDE/kg. Sewage sludge, analysed in Sweden also contained this PeBDE. In mussel and fish collected from different seashores in Japan in the period 1981-85, concentrations of 0.4 and 2.8 1-tg PeBDE/kg wet weight were found in 2 out of 5 mussel samples. No PeBDE was detected in fish (limit of determination < 0.2 ~-tg/kg). Concentrations of 1.9-22 ~-tgfkg, on a fresh weight basis, were reported in liver samples from cod from the North Sea. In Sweden, concentrations of between 7.2 and 64 1-tg 2,2' ,4,4' ,5- PeBDE/kg fat were found in freshwater whitefish and herring collected at different places. Pooled blubber of ringed seal and of grey seal collected in Sweden in 1979-85 contained average concentrations of 1. 7 1-tg and 40 1-tg 2,2',4'4',5-PeBDE/kg fat, respectively. Pooled samples of muscle of rabbits, moose, and suet samples of reindeer collected in 1985-86 in Sweden contained < 0.3 1-tg, 0.64 ~-tg, and 0.26 1-tg 2,2' ,4,4' ,5-PeBDE/kg fat, respectively. Muscle samples of osprey, collected in Sweden in 1982-86, contained an average concentration of 140 1-tg 2,2' ,4,4' ,5- PeBDE/kg fat. The levels of 2 PeBDE isomers in guillemot eggs from the Baltic have increased by one order of magnitude during the last decades. The levels of these isomers in pike from a lake in Southern Sweden also showed an increase (by a factor of about 4).

188 Pentabromodiphenylether

Baltic sediments representing different sampling years also indicate a considerable increase during the last decade. There is minimal information on human exposure, but a rough estimate of exposure of the Swedish population through fish consumption would suggest an intake of 0.1 J.lg PeBDE/person per day.

1. 1.5 Kinetics and metabolism in laboratory animals and humans

The half-life of PeBDE has only been investigated in the perirenal fat in rats. The average half-life was between 25 and 47 days, depending on the sex of the animal and the type of isomer determined.

1. 1.6 Effects on laboratory mammals and in vitro test systems

The acute oral toxicity of commercial PeBDE is low in rats; the dermal toxicity in rabbits is also low. Short-term inhalation exposure in rats and the application of PeBDE to the conjunctival sac in rabbits caused only mild, transient effects. In short-term toxicity studies on rats (4-week and 13-week), dietary concentrations of 100 mg/kg increased liver weights and caused slight histological alterations. Changes consisted of the enlargement of hepatic parenchymal cells, which had a granular appearance and contained eosinophilic "round bodies". Dose­ related increases in total bromine content in the liver occurred and levels remained elevated for as long as 24 weeks. A mild degree of thyroid hyperplasia, which was reversible, was observed. Hepatic enzyme induction and increases in cytochrome P450 c occurred after oral administration of daily doses of PeBDE as low as 0.78 ~-tmol/kg body weight. The results of tests for teratogenicity and mutagenicity were negative. No long-term/carcinogenicity studies have been reported.

1. 1. 7 Effects on humans

No data are available.

189 EHC 162: Brominated diphenyl ethers

1. 1.8 Effects on other organisms in the laboratory and field

Minimal data are available.

1.2 Conclusions

1.2.1 PeBDE

Commercial PeBDE (a mixture of 24-38% tetra-, 50-60% penta-, and 4-8% hexabromodiphenyl ether) is persistent and accumulates in organisms in the environment. Commercial PeBDE is widely used, incorporated in polymers as an additive flame retardant. Contact of the general population is with products made from these polymers. Exposure by extraction from polymers is unlikely. Human exposure to PeBDE via the food chain may occur, since the substance has been detected in organisms in the environment that are human food items, such as fish, shellfish, etc. In fish and birds from Sweden, increasing levels have been measured over the last 2 decades. The acute toxicity of commercial PeBDE is low. There is no information on uptake and loss in mammals. Reproduction, long­ term toxicity, and carcinogenicity studies are not available. The risk to the general population cannot be determined from the available data. No information is available to draw conclusions on occupational exposure levels or the effects of commercial PeBDE. Limited information is available on the toxicity of commercial PeBDE for organisms in the environment.

1.2.2 Breakdown products

PBDF and, to some extent, PBDD are formed when PeBDE (or products containing it) are heated to 400-800 °C. The possible hazards associated with this have to be addressed. Exposure of the general population to PBDF in polymers flame retarded with PeBDE is unlikely to be of significance. Properly controlled incineration does not lead to the emission of significant quantities of brominated dioxins and -furans. Any

190 Pentabromodipheny/ ether

uncontrolled combustion of products containing PeBDE can lead to the generation of unquantified amounts of PBDF/PBDD. The significance of this for both humans and the environment will be addressed in a future EHC on PBDF/PBDD.

1 .3 Recommendations

1. 3. 1 General

Persistence in the environment and accumulation in organisms suggest that commercial PeBDE should not be used. However, if use continues, the following points should be taken into account: • Workers involved in the manufacture of PeBDE and products containing the compound should be protected from exposure using appropriate industrial hygiene measures, the monitoring of occupational exposure, and engineering controls. • Environmental exposure should be minimized through the appropriate treatment of effluents and emissions in industries using the compound or products. Disposal of industrial wastes and consumer products should be controlled to minimize environmental contamination with this persistent and accumulating material and its breakdown products. • Incineration of materials flame retarded with PeBDE should only be carried out in properly constituted incinerators running consistently under optimal conditions. Burning by any other means will lead to production of toxic breakdown products.

1.3.2 Further studies

• Continued monitoring of environmental levels is required. • Methods for the determination of PeBDE in various matrices should be validated. • Because the present toxicological database is inadequate to evaluate the hazards of commercial PeBDE for humans and the environment, and to support its use, the following studies should be done:

191 EHC 162: Brominated diphenyl ethers

additional toxicological, carcinogenicity, and ecotoxicological studies; further investigations on the generation of PBDF under real fire conditions; investigations on possible methods and consequences of recycling of PeBDE-containing polymers; studies on the possibilities of migration from flame­ retarded products.

192 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES,ANAL YTICAL METHODS

2.1 Identity

Chemical structure

6' 6 0 5

4

Drs

Chemical formula: Relative molecular mass: Common name: pentabromodiphenyl ether (PeBDE); pentabromodiphenyl oxide CAS registry number: 32534-81-9 CAS name: 1, 1'-oxybis-pentabromo-benzene, benzene, 1, ~ '-oxybis-, pentabromo

On the basis of the chemical structure, there are 46 possible isomers of pentabromodiphenyl ether.

From: IRPTC (1988).

193 EHC 162: Brominated diphenyl ethers

2.1. 1 Technical product

Trade names DE 71; Bromkal 70-5 DE; FR 1205/1215; Bromkal 70; Bromkal G 1; Pentabromprop; DE-60 F is a mixture of 85% PeBDE and 15% of an aromatic phosphate

Commercial pentabromodiphenyl ether is a mixture of polybrominated diphenyl ethers with the following typical composition (see Table 1): 0-1% tribromodiphenyl ether, 24-38% tetrabromodiphenyl ether, 50-62% pentabromodiphenyl ether, 4-8% hexabromodiphenyl ether (Arias, 1992). DE-71 is primarily a mixture of tetra-, penta-, and hexabromodiphenyl ethers containing low levels of tribromodiphenyl ether ( < 1%) and heptabromodiphenyl ether ( < 2%) (McAllister & Ariano, 1982). Pentabromprop is a mixture of 39% tetra-, 61% penta-, and 9% hexabromodiphenyl ethers. Bromkal 70-5 DE is a mixture of 34.2% tetra-, 59.8% penta-, 5.8% hexa-, and 0.2% heptabrornodiphenyl ethers, but 41.7% tetra- and 45% pentabromodiphenyl ethers, and 7% of a second pentabromodiphenyl ether have also been reported (Nylund et al., 1992). Another manufacturer produces a mixture of 35% tetra-, 58% penta-, and 4% higher brominated diphenyl ethers under the name of Pentabromodiphenyl ether. Bromkal 70 is a mixture containing 36% tetrabromo- and 74% pentabromodiphenyl ether. The bromine contents of the mixtures range from 67 to 71.8% (De Kok et al., 1979). Bromkal 70-5, a mixture of brominated diphenyl ethers containing 67-71% bromine, and an average of about 5 bromines per molecule, also contained various isomers of tri-, tetra-, penta-, and hexabromodiphenyl ethers. However, it is no longer produced commercially (McAllister, 1991). Sundstrom & Hutzinger (1976) identified 2,2',4,4'-tetra- and 2,2' ,4,4' ,5,-PeBDE as the major components of Bromkal 70-5 DE.

194 Pentabromodiphenyl ether

2.2 Physical and chemical properties

Pentabromodiphenyl ether (PeBDE) is a clear, amber to pale yellow, highly viscous liquid, with an organic smell. Under conditions of fire, hydrogen bromide and/or bromine occur.

Melting point -7 to -3 oca Boiling point > 300 oc (decomposition starts above 200°C) Specific gravity 2.28 at 25 oc; 1.78 at 40 oc Vapour pressure 9.3 mmHg at 22 ocb (6.26-6.66 Torr at 25 oq Solubility Insoluble in water (9 x w-7 mg/litre at 20 °C), methanol 10 g/litre at 25 °C, soluble in other organic solvents such as chloroform, benzene, toluene, acetone,carbon­ tetrachloride, and methylene chloride Viscosity at 50 oc 1-6 Pa (150 000 cp at 25 oc; 1500 cp at 60 oq n-Octanol/water partition coefficient (log Pow) 6.64-6.97

From: Great Lakes Chemical Corporation (undated a); Kalk (1982); Kopp (1990); US EPA (1989); Hallenbeck (1993); US Testing Comp. (1985).

2.3 Analytical methods

McAllister & Ariano (1982) developed a method for the determination of the arbitrarily defined "bromination level" of PeBDE (DE-71), both as the neat material and as a formulation in DE-60 F, and for the quantitative determination of aromatic phosphate ester in DE-60 F. The sample is dissolved in

195 EHC 162: Brominated diphenyl ethers

dibromomethane contammg an internal standard and the components separated by gas chromatography. A multiresidue method has been developed for the determination of PBDE residues in environmental samples (see General Introduction, section 2.1 and Table 2).

196 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

Pentabromodiphenyl ether has not been reported to occur naturally (see General Introduction, section 1.1).

3.2 Anthropogenic sources

3. 2. 1 Production levels and processes

Pentabromodiphenyl ether is synthesized by treating diphenyl

ether with 5 equivalents of Br2 at 30-65 oc in the presence of powdered iron (US EPA, 1986). The actual worldwide consumption of PeBDE per year is 4000 tonnes. In the Federal Republic of Germany, in 1988, the approximate level of use in plastics was 200-400 tonnes/year. The total use of penta- and hexabromodiphenyl ethers in the Netherlands in 1988 was estimated to be 350 tonnes (Anon., 1989b). Production levels are not available.

3.2.2 Uses

PeBDE is used as an additive in epoxy resins, phenol resins, unsaturated polyesters, polyurethane flexible, and textiles.

197 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

4. 1 Pyrolysis

PeBDE (Bromkal 70, 70-5 DE, G1) were heated in a quartz tube at 700, 800, or 900 oc and the concentrations of PBDD and PBDF determined. Monobromo- to pentabromodibenzofurans, as well as monobromo- to tetrabromodioxins, were found in yields of up to 90% in all 3 Bromkal samples. The optimal temperatures of formation were between 700 and 800 oc (Thoma eta!., 1987a). Bromkal 70-5-DE was pyrolysed at 600, 700, 800, and 900 °C, in the absence of oxygen, in a SGE pyrojector and the residues analysed by GC/MS in an on-line operation. The pyrolysis of Bromkal 70-5-DE yielded polybromobenzenes (PBBz), polybromophenols (PBP), and brominated dibenzofurans. Because this pyrolysis is performed in a pyrojector with a helium current, incorporation of oxygen is impossible, consequently dioxins do not form (Thoma & Hutzinger, 1987, 1989).

4.2 Workplace exposure studies

In the pr

4.3 Bioaccumulation

Carp exposed for 8 weeks to commercial pentabromodiphenyl ether at 10 or 100 llg/litre showed bioconcentration factors of more than 10 000 (CBC, 1982).

198 Pentabromodiphenyl ether

4.4 Ultimate fate following use

For the ultimate fate of PeBDE following use see section 6.1 of the General Introduction.

199 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

5.1 Levels in the environment

5.1.1 Sediment and sewage sludge

Sediment samples were taken from the rivers near the centre of Osaka City and marine sediments, from different estuaries in Japan and from Osaka Bay, during the period 1981-83. No PeBDE was found ( < 2 llg/kg dry weight) in 9 estuarine or marine sediment samples. PeBDE was present in 5 out of 6 river sediment samples at concentrations of 9-28 llg/kg on a dry weight basis (Watanabe, 1987; Watanabe eta!., 1987b). Organic extracts, made from coastal sediments, collected off­ shore from Barcelona, were analysed for the presence of organa­ halogenated chemicals. A diversity of organohalogenated compounds were found, among them PeBDE (Fernandez et al., 1992). Sellstrom et a!. (1990a,b) analysed sediment samples, taken upstream and downstream from a factory, for the presence of tetrabromobisphenol-A and derivatives. Both tetrabromobisphenol A and 2,2' ,4,4' ,5-pentabromodiphenyl ether were found. The levels found in upstream and downstream sediments were 8.2 and 1200 JLglkg (ign loss), respectively. A laminated sediment core collected in the southern part of the Baltic Proper (Bornholm Deep) was analysed for 2,2' ,4,4' ,5- PeBDE. The core was cut into 5 mm slices down to 50 mm depth and in 10 mm slices from 50 to 90 mm depth. The concentration of PeBDE at a depth of 5 mm was 0.98 llg/kg IG and decreased more or less gradually in the deeper layers to approximately 0.05 llg/kg at a depth of 40 mm. Below this depth, levels were mostly not detectable (Nylund eta!., 1992). Sellstrom et al. (1990a,b) analysed sewage sludge and found 19 llg 2,2' ,4,4' ,5-pentabromodiphenyl ether/kg ign loss. Two sewage samples were collected from a Swedish treatment plant (Gothenburg) in September 1988 and analysed for PBDE.

200 Pentabromodiphenyl ether

One homogenate was composed of samples (40 g/day) taken over a 32-day period with little rain. Another homogenate was composed of samples (100 g/day) taken during a rainy period of 7 days. Both TeBDE and PeBDE were found. The concentration of 2,2',4,4',5- PeBDE was 19 p.g/kg; concentrations of PeBDE of unknown structures were 3.4 and 3.7 p.g/kg and total PeBDE, 37-38 p.g/kg IG (Nylund et al., 1992).

5. 1. 2 Fish and shellfish

Mussels and some species of fish, e.g., mullet, goby, and Japanese sea bass, were collected from different seashores in Japan from 1981 to 1985. Other fish species were purchased from a commercial wholesale source in Osaka Prefecture in 1981. In 2 out of 5 mussel samples, levels of 0.4 and 2.8 p.g PeBDE/kg wet weight were found. In 12 fish samples, no PeBDE ( < 0.2 p.g/kg wet weight) was found (Watanabe, 1987; Watanabe eta!., 1987b). 2,2' ,4,4' ,5'-Pentabromodiphenyl ether (PeBDE) was found in cod liver (2 samples from each region) from the southern, central, and northern regions of the North Sea, in 1982-87. Levels were 3.6 and 22.0 p.g/kg; 4.9 and 7.2 p.g/kg; and 1.9 and 6.5 p.g/kg, respectively, on a product basis (De Boer, 1989). A multiresidue analytical method was applied to pooled muscle samples of 35 freshwater whitefish (Coregonus sp.), 15 samples of arctic char (Salvelinus a/pinus), and a total of 260 samples of herring (Ciupea harengus), collected at different places in Sweden during the period 1986-87. The average concentrations of 2,2' ,4,4' ,5-pentabromodiphenyl ether were 7 .2, 64, and 9.8-46 p.g/kg lipid, respectively (Jansson eta!., 1993). Samples of bream, pike, perch, and trout from Sweden were shown to contain 2,2' ,4,4' ,5-PeBDE in concentrations of 2.3- 2.4 p.g/kg, 60-1100 p.g/kg, 380-9400 p.g/kg, and 130-590 p.g/kg lipid, respectively. Another PeBDE isomer of unknown structure was also found in all fish samples at concentrations of 11-37 p.g/kg, 25-640 p.g/kg, 230-3500 p.g/kg, and 33-150 p.g/kg lipid, respectively. The samples represent both background and industrialized areas (Sellstrom et a!., 1993a). A study of TeBDE and PeBDE in banked samples of pike from a lake in Southern Sweden revealed concentrations increasing

201 EHC 162: Brominated diphenyl ethers

from 40 f.Lg/kg lipid in 1974 to 180 f.Lg/kg lipid in 1991 (Sellstrom et al., 1993b). Kruger (1988) sampled 40 freshwater fish of various species from the waters of North-Rhine Westfalia in Germany and found PBDE in concentrations ranging from 18 to 983 f.Lg/kg fat, measured as Bromkal 70-5DE. Concentrations in 6 sea fish from the Baltic Sea ranged from 12 to 57 Jig PBDE/kg fat and those in 11 fish from the North Sea, from 1 to 120 Jig/kg fat, measured as Bromkal 70-5DE.

5. 1.3 Aquatic mammals

Pooled samples of blubber of 7 ringed seals (Pusa hispida), collected in 1981, and of 8 grey seals (Halichoerus grypus), collected in 1979-85, in Sweden were analysed using a multiresidue analytical method. The average concentrations of 2,2' ,4,4' ,5-pentabromodiphenyl ether were 1. 7 and 40 JLglkg lipid, respectively (Jansson eta!., 1993).

5. 1.4 Terrestrial mammals

Pooled samples of muscle of 15 rabbits (Orytolagus cuniculus), 13 samples of moose (Alces alces), and 31 suet samples of reindeer, collected in the period 1985-86, in Sweden, were analysed using a multiresidue method. The average concentrations for rabbits, moose, and reindeer, were < 0.3, 0.64, and 0.26 Jig 2,2' ,4,4' ,5-pentabromodiphenyl ether/kg lipid, respectively (Jansson eta!., 1993). Concentrations of 10 Jig PBDE/kg fat, measured as Bromkal 70-DE, were detected in samples from 8 seals from Spitzbergen (Kruger, 1988). PBDE, measured as Bromkal 70-DE, was detected in 4 samples of cow's milk at concentrations ranging from 2.5 to 4.5 Jig/kg fat (Kruger, 1988).

5. 1.5 Birds

Pooled samples of muscle of 35 osprey (Pandion haliaetus), collected in Sweden in the period 1982-86, were analysed using a

202 Pentabromodiphenyl ether

multiresidue method, for 2,2' ,4,4' ,5-pentabromodiphenyl ether. The average concentration was 140 J.Lg/kg lipid (Jansson et al., 1993). Newborn starlings from different places in Sweden have been shown to contain 2.3-4.2 ILg 2,2' ,4,4' ,5-PeBDE/kg lipid and an unidentified PeBDE at 0.62-1.1 J.Lglkg lipid (Sellstrom et al., 1993a). The same authors reported concentrations of the same two PeBDE isomers in guillemot eggs from the Baltic Sea, caught during the period 1970-89 (see Table 27).

Table 27. Average PeBDE concentrations (pg/kg lipid) in guillemot eggs from the Baltic Sea"

Sampling year 2,2' .4.4',5-PeBDE PeBDE (unknown structure)

1970 24 4.2

1974 48 8.5

1975 33 4.6

1976 130 32

1979 130 37

1982 200 44

1983 210 49

1986 260 48

1987 160 40

1989 240 61

8 From: Sellstrom et al. (1993a).

5.2 General population

Samples of human milk from 26 women in North Rhine Westfalia, Germany, were analysed for PBDE, measured as Bromkal 70-DE. Concentrations in the milk from 25 of the women

203 EHC 162: Brominated diphenyl ethers

ranged from 0.62 to 11.1 1-1-g/kg fat. In one Chinese woman, a level of 50 1-1-g/kg fat was found (Kruger, 1988). In Sweden, the major human exposure is via fish-related food and the levels of PeBDE in fish may be used to estimate this exposure route. Normal fish intake in Sweden is about 30 g/day, and, if herring is used as a model fish, this will give an estimate of intake of about 0.1 1-1-g PeBDE/person per day (Personal Communication, Jansson).

204 6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

The half-life of pentabromodiphenyl ether (Bromkal 70) in perirenal fat was investigated in groups of 3 male and 3 female Wistar rats (weight 160-180 g) following a single oral dose of 300 mg/kg body weight in peanut oil. Animals from the groups were killed on days 1, 2, 3, 4, and 7 and then at weekly intervals for 10 weeks. The perirenal fat was collected and analysed. The half-lives of 2 PeBDE isomers, following extraction and separation with HPLC (containing also tetrabromo- and hexabromodiphenyl ethers), are summarized in Table 28 (Von Meyerinck et al., 1990).

Table 28. Half-lives of PeBDE in male and female rats8

PBDE Half-lives 1n female rats Half-lives 1n male rats 1n days 1n days

PeBDE(1 )b 47.4 (42.5-52.4) 36.8 (33.7-40.0)

PeBDE(2)b 25.4 (22.6-28.4) 24.9 (22.6-27 .1)

8 From: von Meyerinck et al. (1990). b(1) and (2) means two different 1somers. Confidence interval, P=0.05.

205 7. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS

7.1 Single exposures

7.1.1 Oral

Groups of 5 male, albino Charles River CD rats were administered (by gavage) 50, 500, or 5000 mg commercial PeBDE (in corn oil)/kg body weight and observed for 14 days. The rats receiving 50 and 500 mg/kg survived and exhibited normal body weight gain. Four out of 5 rats dosed with 5000 mg/kg died within 5 days. The remaining rats survived and showed normal growth (Great Lakes Chemical Corporation, undated a). Groups of 5 male and 5 female Wistar rats were administered 2400, 4800, 6048, 7621, or 9600 mg commercial PeBDE/kg body weight. The substance was given by gavage as an 80% w/v suspension in maize oil after which the rats were observed for 44

days. The acute oral LD50 was 7400 mg/kg for males and 5800 mg/kg body weight for females. The symptoms seen were decrease in growth, diarrhoea, piloerection, reduced activity, clonic persistent tremors of the fore limbs, and red staining around eyes and nose. A continual chewing movement of the jaws was also seen. Post-mortem examination revealed pale (mottled), enlarged, necrotic livers and multiple small ulcerations of the gastric mucosa (Great Lakes Chemical Corporation undated a).

7. 1. 2 Dermal

Commercial PeBDE was applied to the clipped intact or abraded skin of groups of 2 male and 2 female New Zealand white rabbits at doses of 200 or 2000 mg/kg body weight, for 24 h, under an occlusive dressing. The rabbits were observed for 14 days. No animals died during the observation period. At 200 and 2000 mg/kg, normal body weight gain or only a slight decrease in growth was seen (Great Lakes Chemical Corporation, undated a).

206 Pentabromodiphenyl ether

7. 1.3 Inhalation

The inhalation LC50 for the rat is > 200 mg/litre (Kopp, 1990). Groups of 10 male and 10 female Charles River CD rats were exposed for 1 h to an aerosol mist of commercial PeBDE mixed with corn oil at concentrations of 2 or 200 mg/litre of air and subsequently observed for 14 days. No rats died during the study. The rats exposed to 2 mg/litre exhibited increased and then decreased motor activity, erythema, and eye squint during the exposure and for the following 24 h. After 24 h, and up to the end of the study, the animals appeared normal. During exposure to 200 mg/litre, the same signs were observed but also lacrimation, salivation, and tachypnoea. At 24 h and 48 h, 2 rats exhibited nasal congestion and one rat showed respiratory congestion after 72 h. From day 4 to day 14, the animals appeared normal and showed normal body weight gain (Great Lakes Chemical Corporation, undated a).

7. 2 Short-term exposure

Charles River CD rats were fed dietary levels of 0, 100, or 1000 mg commercial PeBDE (dissolved in corn oil)/kg daily for 28 days. There were 10 male and 10 female animals in each group. No changes were noted in behaviour, appearance, food con-sumption, or body weight gain. Absolute and relative liver weights were significantly increased in female rats fed with 100 mg/kg and in male and female rats fed with 1000 mg/kg. The liver lesions were more prevalent in male rats and increased with dose. A significant decrease in the relative weights of the pituitary. and adrenal glands was found at the highest dose level. No compound-related, gross pathological lesions were noted. Micro­ scopically, enlargement of the centrolobular and midzonal liver parenchyma cells was seen. and the cytoplasm included areas with a finely granular appearance; eosinophilic "round bodies" in enlarged hepatocytes were seen in the animals at both dose levels. Several rats from both the 100 mg and the 1000 mg/kg groups had slight to moderate hyperplasia of the thyroid, but control animals also had thyroid glands that could be considered hyperplastic. In thyroid glands designated as hyperplastic, most follicles were very small, devoid of colloid, and lined by basophilic columnar fol­ licular epithelium. Whether these thyroid changes were compound-

207 EHC 162: Brominated diphenyl ethers

related is not clear. Dose-related increases in total bromide levels in liver tissues from the (pooled) treated rats were 6-12 times higher than those in the controls (Great Lakes Chemical Corporation, undated a). Commercial PeBDE (DE-71) was given in the diet to 3 groups of 30 male and 30 female CD Sprague-Dawley rats. Dosage levels of 0, 2, 10, or 100 mg/kg per day were administered for 90 days. Ten animals per sex were sacrificed after 4 weeks and after 90 days, 5 animals were sacrificed after a 6-week recovery period, and 5 animals, after a 24-week recovery period. No increased mortality or clinical effects were observed. Decrease in food consumption was seen in high-dose females and a decrease in body weight was observed in high-dose males and females. Haema­ tology parameters and liver function were normal, but increased cholesterol values were observed for high-dose animals. Tri­ iodothyronine (T3) levels were normal, but tetraiodothyronine (T4) levels were decreased (not dose-related) in the 10 mg and 100 mg/kg group; an increase in serum total bromide levels was observed in these 2 groups after 4 and 13 weeks. Compound­ related increases in liver and urine porphyrins were observed in the high-dose animals after 13 weeks. Urine porphyrin levels were 13 times higher in females and up to 8 times higher in males and liver porphyrin levels were almost 400 times higher than those of the controls. Compound-related increases in tissue total bromine levels were noted in all tissues for males and females at both the low- and high-dose levels (mid-dose levels not deter­ mined). During the recovery period, a slow decrease in the total bromine levels was noted, but, even after 24 weeks, the levels did not reach the control values, especially in the highest dose group. Relative liver weights in the 10 and 100 mg/kg groups were increased, but, during the recovery period, liver weights that were still higher after 6 weeks were normal after 24 weeks. Micro­ scopic examination revealed hepatocytomegaly and thyroid hyperplasia. The thyroid hyperplasia was reversible in 24 weeks recovery period, but the liver still showed slight hepatocytomegaly in the 10 and 100 mg/kg group. At the lowest dose level (2 mg/kg), the only effect observed after 24 weeks' recovery, i.e., liver cell degeneration and necrosis, was seen in females, but not in males (Great Lakes Chemical Corporation, undated a).

208 Pentabromodiphenyl ether

7.3 Long-term exposure

No data are available.

7.4 Skin and eye irritation; sensitization

7.4. 1 Skin irritation

Commercial PeBDE was applied, under occlusion, to the clipped intact or abraded skin of groups of 3 male and 3 female New Zealand white rabbits at a dose of 0.5 ml (approximately 1135 mg). After 24 h, the wrappings were removed and the backs of the rabbits washed and examined for signs of irritation. The examinations were repeated at 72 h. At 24 and 72 h, no, or only very slight, erythema was noted. No oedema was seen (Great Lakes Chemical Corporation, undated a).

7.4.2 Eye irritation

A single application of 0.1 ml commercial PeBDE was instilled into the conjunctival sac of the eyes of 3 male, and 3 female, New Zealand white rabbits. Examinations were carried out at 24, 48, and 72 h, and at 7 days. At 24 h, all rabbits showed slight redness, slight chemosis, and slight discharge of the conjunctivae. These symptoms subsided during 7 days. At 7 days, slight alopecia around the eyelid was seen in 2 of the 6 animals. No irritation of the iris was observed. Examination at 72 h revealed slight evidence of corneal damage in one of the 6 animals (Great Lakes Chemical Corporation, undated a).

7. 5 Reproductive toxicity, embryotoxicity, and teratogenicity

Pregnant female rats were given corn-oil suspensions of commercial PeBDE, by gavage, at dosages of 0, 10, 100, or 200 mg/kg body weight per day, on days 6-15 of gestation. The material was not teratogenic. The maternal no-effect level was 10 mg/kg and the embryo/fetal no-effect level was 100 mg/kg body weight. Inhibition of maternal body weight gain occurred at doses of 100 or 200 mg/kg. A slight, nonstatistically significant,

209 EHC 162: Brominated diphenyl ethers

reduction in average fetal body weight per litter was found at the highest dose level (BFRIP, 1990) (no further details).

7.6 Mutagenicity and related endpoints

Commercial PeBDE was examined for mutagenic activity at a number of concentrations in a series of in vitro microbial assays using Salmonella typhimurium TA98, TA100, TA1535, and TA1537 and Saccharomyces cerevisae in the presence, and absence, of liver microsomal enzyme preparations from Aroclor­ induced rats. A negative result was obtained with and without microsomal activation (Great Lakes Chemical Corporation, undated a).

7. 7 Carcinogenicity

No data are available.

7.8 Other special studies

Commercial PeBDE in corn oil was administered, by gavage, to 6 male Sprague-Dawley rats (200-250 g) for 90 days. When the original doses of 6.25, 12.5, and 25 ~-tmol/kg per day revealed extensive induction, the study was repeated at doses of 0. 78, 1.56, and 3.13 ~-tmollkg per day. When the lower dose levels were tested, even the lowest dose of PeBDE (0.78 ~-tmol/kg) caused increases in 0-ethyl-0-p-nitrophenyl phenylphosphonothiate (EPN) detoxification, p-nitroanisole demethylation, and NADPH cytochrome c reductase and cytochrome P450 activity. A clear dose-response relationship was found for EPN detoxification and p-nitroanisole demethylation. When the animals were allowed a 30-day recovery period following the last (90th) dose, elevations in these two measurements were still observable at all doses, though increased NADPH cytochrome c reductase activity was found only at the highest dose. Within this period, the cytochrome P450 content had returned to normal. Even after 60 days recovery, elevations were noted in EPN detoxification and p-nitroanisole demethylation at the 1.56 and 3.13 ~-tmol/kg levels. No histo­ logical liver abnormalities were observed in rats treated with doses of 3.13 ~-tmollkg or less (Carlson, 1980b).

210 Pentabromodiphenyl ether

In another study, rats (200-250 g) were administered commercial PeBDE at 0.1 mmol!kg per day, in corn oil, by gavage, for 14 days. In addition to the above described effects on the enzymes, increases in the activities of UDP-glucuronyl­ transferase and benzo[a]pyrene-hydroxylase were found 24 h after the seventh dose (Carlson, 1980a). Von Meyerinck et al. (1990) studied the hepatic microsomal enzyme inducing potential of Bromkal 70 in Wistar rats. A series of dosing regimes was used, which varied from single oral doses of up to 300 mg/kg body weight to 28 daily oral doses of 50 mg/kg body weight. In all cases, the vehicle was peanut oil (1 ml!kg), which was also administered to the vehicle control group. There were 3 male and 3 female rats per group, except in the 28-day study in which 4 male and 4 female rats were used. The treatments resulted in 31-53% increases in liver weight, 2.3- 3.9-fold increases in cytochrome P450 c levels, up to 2-fold increases in benzphetamine N-demethylation activity, and 2.2-5.3- fold increases in benzo(a)pyrene oxidation. Increases in ethoxyresorufin 0-deethylation activity ranged from not detectable to 0.35 nmol/min mg microsomal protein in control groups to between 4.1 and 16.6 nmol!min mg microsomal protein in treatment groups. These activities were sex and dose dependent. The most sensitive parameter was ethoxyresorufin 0-deethylase induction, which showed no significant response in rats dosed once with 3 mg PeBDE/kg and killed 3 days later. Commercial PeBDE (Bromkal 70-5 DE) showed the induction of ethoxyresorufin 0-deethylase activity in H-4-11 E cells (Hanberg eta!., 1991).

211

TETRABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

Tetrabromodiphenyl ether is not manufactured or used. No data are available on the following topics: • Effects on laboratory mammals and in vitro test systems • Effects on humans • Effects on other organisms in the laboratory and field • Previous evaluations by international bodies.

1.1 Summary and evaluation

1. 1. 1 Identity, physical and chemical properties

Commercial tetrabromodiphenyl ether, consisted of 41% tetra-, 45% penta-, and 7% hexabromodiphenyl ethers and about 7% PBDE of unknown structure. On the basis of the chemical structure, there are 42 possible isomers of tetrabromodiphenyl ether. Virtually no data are available on physical and chemical properties, except that the n-octanol/water partition coefficient (log

P0 w) is 5.87-6.16.

1. 1.2 Production and uses

There is a report of the production (use) of about 1000 tonnes of TeBDE in Japan in 1987. There is no known current production under the name of tetrabromodiphenyl ether, but TeBDE is present in quantities of from 24 to 38% in commercial pentabromodiphenyl ether.

1. 1.3 Environmental transport, distribution, and transformation

Components of commercial TeBDE have been found in biota, sediment, and sewage sludge samples. Commercial TeBDE components (containing approximately equal quantities of PeBDE) are likely to be persistent and to bioaccumulate.

215 EHC 162: Brominated diphenyl ethers

Pyrolysis studies with commercial TeBDE showed that PBDF and PBDD are formed at 800 °C. Higher PBDF and PBDD were not found.

1.1.4 Environmental levels and human exposure

TeBDE was found, in Japan, in river sediment at concen­ trations of 12-31 p.g/kg dry weight and, in Sweden, at concen­ trations of up to 840 p.g/kg ign. loss, respectively. TeBDE was also found in sewage sludge in Sweden, at a concentration of 15 p.g/kg. Mussels and fish, collected at different places in Japan, contained TeBDE in concentrations ranging from < 0.1 to 14.6 p.g 2,2',4,4'-TeBDE/kg wet weight. In Sweden, different types of fish were collected from rivers and analysed for 2,2' ,4,4'­ TeBDE. The mean concentrations ranged from ND ( < 0.1mg/kg) to 110 mg/kg fat. The analysis indicated that there was at least one local source of pollution in a certain river. Whitefish, arctic char, and herring, collected at different places in Sweden in 1986-87, contained concentrations of 15, 400, and 59-450 p.g 2,2',4,4'­ TeBDE/kg fat, respectively. Fish collected from rivers in Germany contained up to 1 mg TeBDE/kg fat. In herring and in the liver of cod, collected in the southern, central, and northern North Sea, in the period 1983-89, a decreasing trend in the concentrations of TeBDE was found from the southern region to the northern region. In the herring, concentrations of 8.4-100 p.g 2,2',4,4'-TeBDE/kg, on a fat basis, were found. The muscle tissue of birds nesting and wintering in the Baltic Sea, the North Sea, and Spitzbergen, contained from 80 to 370 p.g 2,2',4,4'-TeBDE/kg, on a fat basis. Osprey collected in Sweden in the period 1982-86, contained average concentrations of 1800 t~-glkg fat. Increasing trends in the concentrations of 2,2' ,4,4'-TeBDE have been indicated for Baltic sediments, freshwater fish, and sea bird eggs from Sweden.

216 Tetrabromodiphenylether

The blubber of seals collected in the Baltic Sea and Spitzbergen showed concentrations of 10-730 Jlg 2,2',4,4'­ TeBDE/kg, on a fat basis. The chromatographic pattern of the PBDE was similar to that of Bromkal 70-5. Pooled samples of the blubber of ringed seals and grey seals, collected in Sweden in 1979-85 showed concentrations of 47 J.Lg and 650 J.Lg 2,2' ,4,4'­ TeBDE/kg fat, respectively. Pooled muscle samples of terrestrial mammals, e.g., rabbits, moose and reindeer, collected in 1985-86 in Sweden, showed average concentrations of < 2, 0.82, and 0.18 J.Lg 2,2',4,4'­ TeBDE/kg fat, respectively. Levels of 2.5-4.5 J.Lg PBDE/kg fat, measured as Bromkal ?ODE, were found in 4 samples of cow's milk in Germany. PBDE, as Bromkal ?ODE, was found in the milk of 25 women in Germany at concentrations ranging from 0.62 to 11.1 J.Lg/kg fat. A rough estimate of exposure via fish consumption among the Swedish population would suggest an intake of 0.3 J.Lg TeBDE/ person per day.

1.1.5 Effects on laboratory mammals and in vitro test systems

There are no data on TeBDE itself, but acute and short-term data are available for commercial PeBDE containing 41% TeBDE.

1.1.6 Kinetics and metabolism in laboratory animals and humans

Minimal data are available.

1.1. 7 Effects on humans

No data are available.

1. 1.8 Effects on other organisms in the laboratory and field

No data are available.

217 EHC 162: Brominated diphenyl ethers

1.2 Conclusions

1.2.1 TeBDE

Components of commercial TeBDE (a mixture of 41% 2,2',4,4'-tetra-; 45% 2,2',4,4',5'-penta-; 7% hexa-, and 7-8% polybrominated diphenyl ethers with an unknown structure) are persistent and accumulate in organisms in the environment. TeBDE as a component of pentabromodiphenyl ether is widely incorporated in polymers as an additive flame retardant. Contact of the general population is with products made from these polymers. Exposure by extraction from polymers is unlikely. Human exposure to TeBDE, via the food chain, may occur, because the substance has been detected in organisms in the environment that are human food items, such as fish, shellfish, etc. In fish and birds from Sweden, increasing levels have been measured over the last two decades. There is a lack of information concerning short-, long-term toxicity/carcinogenicity, and reproduction studies. Furthermore, information on kinetics and metabolism in laboratory animals and humans is not available. The risk for the general population cannot be determined on the basis of available data. No information is available to draw conclusions on occupational exposure levels or the effects of TeBDE. No data are available on the toxicity of commercial TeBDE for organisms in the environment.

1.2.2 Breakdown products

PBDF and PBDD are formed when TeBDE are heated to 800 ac. The possible hazards associated with this have to be addressed. Exposure of the general population to PBDF in polymers, flame retarded with TeBDE, is unlikely to be of significance. Properly controlled incineration does not lead to the emission of significant quantities of brominated dioxins and furans. Any uncontrolled combustion of products containing TeBDE can lead to

218 Tetrabromodiphenyl ether

the generation of of unquantified amounts of PBDF/PBDD. The significance of this for both humans and the environment will be addressed in a future EHC on PBDF/PBDD.

1 .3 Recommendations

1. 3. 1 General

Because of their persistence in the environment and accumulation in organisms, it is recommended that TeBDE should not be used. However, should use continue, the following points must be taken into account: • Workers involved in the manufacture of TeBDE and products containing the compound should be protected from exposure using appropriate industrial hygiene measures, the monitoring of occupational exposure, and engineering controls. • Environmental exposure should be minimized through the appropriate treatment of effluents and emissions in industries using the compound or products. Disposal of industrial wastes and consumer products should be controlled to minimize environmental contamination with this persistent and accumulating compound and its breakdown products. • Incineration of materials, flame retarded with TeBDE, should only be carried out in properly constituted incinerators running under optimal conditions. Burning by any other means will lead to the production of furan breakdown products.

1.3.2 Further studies

• Continued monitoring of environmnental levels is required. • Analytical methods for TeBDE in various matrices should be validated. • Because the present toxicological data base is inadequate to evaluate the hazards of commercial TeBDE for humans

219 EHC 162: Brominated diphenyl ethers

and the environment, if use is continued, the following studies should be done: additional toxicological, carcinogenicity, and eco­ toxicological studies; further investigations on the generation of PBDF under real fire conditions; investigation into possible methods and consequences of recycling of TeBDE-containing polymers; investigations of the possibility of migration from flame-retarded products.

220 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2.1 Identity

Chemical structure:

5

4' 4

Chemical formula: Relative molecular mass: 485.82 Common names: tetrabromodiphenyl ether (TeBDE) tetrabromodiphenyl oxide CAS registry number: 40088-47-9 CAS name: 1.1' -oxybis-tetrabromo-benzene

On the basis of the chemical structure, there are 42 possible isomers of tetrabromodiphenyl ether.

2.2 Physical and chemical properties

The technical product consist of 41.7% (41 %) of 2,2',4,4'­ tetrabromodiphenyl ether, 44.4% (45%) 2,4,5,2' ,4'-pentabromo­ diphenyl ether, 6% (7%) hexabromodiphenyl ether and 7.6% PBDE of an unknown structure (see also pentabromodiphenyl ether

221 EHC 162: Brominated diphenyl ethers

and Table 1) (Sundstrom & Hutzinger, 1976; De Kok et al., 1979; US EPA, 1984; De Boer, 1989).

n-Octanol/water partition coefficient (log pow): 5.87-6.16

From: Pijnenburg & Everts (1991).

2.3 Analytical methods

A multiresidue method has been developed for the analysis of PBDE residues in environmental samples (see General Intro­ duction, section 2.1 and Table 2).

222 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

Tetrabromodiphenyl ether has not been reported to occur naturally (see General Introduction, section 1.1).

3.2 Anthropogenic sources

3. 2. 1 Production levels and processes

See sections 2 and 3 of Pentabromodiphenyl ether.

3.2.2 Uses

A thousand tonnes of tetrabromodiphenyl ether (TeBDE) were used in Japan in 1987 (Watanabe, 1987c).

223 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

4.1 Pyrolysis

The pyrolysis of Bromkal 70-DE (a mixture of tetrabromodiphenyl ether and pentabromodiphenyl ether) resulted in the formation of high levels of PBDF and PBDD: approximately 60%. The substance was pyrolysed at 800 oc in a quartz tube for 10 min (Thoma et a!., 1986). Bromkal 70-DE produced complex mixtures of mono- to pentabromodibenzofurans and of mono- to tetrabromodibenzodioxins. Higher PBDF and PBDD were not found (Zacharewski et a!., 1988).

4. 2 Ultimate fate following use

For the ultimate fate of TeBDE following use in the environment see section 6.1. of the General Introduction.

224 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

5.1 Environmental levels

5. 1. 1 Soil and sediment

Watanabe et a!. (1987b) determined the residues of TeBDE in 9 marine and/or estuarine sediment samples and 6 fresh water river sediment samples collected at different sites in Osaka during 1981-83. The nine marine and/or estuarine samples did not contain TeBDE (limit of determination < 2 ~-tg/kg). Five out of 6 river sediment samples contained 12-31 1-tg TeBDE/kg. Sediment samples taken upstream and downstream from a factory were analysed for the presence of tetrabromobisphenol A (TBBP-A) and its dimethylated derivative. Besides TBBP-A, 2,2' ,4,4' -tetrabromodiphenyl ether was also found. The levels found upstream and downstream were 3.5 and 840 ~-tg/kg (IG), respective! y (Sellstrom et a!., 1990a, b). A laminated sediment core collected in the southern part of the Baltic Proper (Bornholm deep) was analysed for 2,2',4,4'­ TeBDE. The core was cut into 5 mm slices down to 50 mm depth and in 10 mm slices from 50 to 90 mm depth. The concentration of TeBDE at 5 mm depth was 1.6 ~-tg/kg IG and decreased gradually to 0.13 ~-tg/kg at 40 mm depth. At a depth of 90 mm, the concentration was 0.06 ~tglkg (Nylund eta!., 1992). Sellstrom et a!. (1990b) analysed sewage sludge and found 15 1-tg 2,2' ,4,4'-tetrabromodiphenyl ether/kg IG. Two sewage samples were collected from a Swedish treatment plant (Gothenburg) in September 1988 and analysed for PBDE. One homogenate was composed of samples (40 g/day) taken during a 32-day period with little rain. Another homogenate was composed of samples (100 g/day) taken during a rainy period of 7 days. TeBDE and PeBDE were found. The concentration of 2,2',4,4'-TeBDE was 15 ~-tg/kg IG (Nylund eta!., 1992).

225 EHC 162: Brominated diphenyl ethers

5. 1. 2 Fish and shellfish

Watanabe et a!. (1987b) determined the levels of TeBDE in fish and mussels collected from different places in Japan in 1981- 85. In total, 42 samples of mussel, mullet, goby, sardine, Japanese sea bass, horse mackerel, and hairtail, were analysed. Seven out of 17 fish and shellfish samples collected in the Osaka area contained 0.1-14.6 11g TeBDE/kg and 3 samples of mussels from Osaka bay contained 1.6-14.6 11g/kg (wet weight). Single samples of sardine, Japanese sea bass, mackerel and hairtail contained levels ranging from 0.1 to 0.8 11g TeBDE/kg. The other species did not contain TeBDE (limit of determination < 0.1 llg/kg). De Boer (1989, 1990) measured the concentration of 2,2' ,4,4'-tetrabromodiphenyl ether in the liver of cod (Gadus morhua), collected in the southern, central, and northern North Sea, in the period 1983-89. Each sample consisted of 25 fishes. The highest levels (up to 360 11g/kg) were found in the liver of cod from the southern part and the lowest levels (up to 68 11g/kg on a fat basis) in the northern part of the North Sea. The concentrations showed a decreasing trend from the southern region to the northern region. Herring (Clupea harengus) collected in the 3 areas and the Straits of Dover in 1985, contained average concentrations of 8.4-100 11g 2,2',4,4'-TeBDE/kg on a fat basis. Eels (Anguilla anguilla) collected in Dutch freshwater (rivers and lakes) at 10 places were analysed for the presence of 2,2' ,4,4'­ TeBDE, during the period 1983-89. The concentrations ranged from < 20 to 1700 11g/kg, on a fat basis. In these marine and freshwater fish, 2,2',4,4'-TeBDE was always found as the main component, i.e., 70% of the total brominated diphenyl ethers. Fish were collected from 5 different localities along the Viskan and Haggan river system and the Klosterfjorden bay in Sweden. Muscle and, in some cases, also the liver of bream (Abramis brama), eel (Anguilla anguilla), pike (Esox lucius), sea trout (Salmo ocla), and tench (Tinea tinea) were analysed. Expressed on a fat weight basis, the highest level found was 110 mg PBDE/kg in the liver of a pike. This pike specimen contained 27 mg PBDE/kg fat in the muscle tissue. In addition to the 3 main components (1 tetrabromo- and 2 pentabromo-isomers), another tetrabromo- as well as 1 tribromo- and 2 hexabromo-

226 Tetrabromodiphenyl ether

isomers were identified by GC/MS. The maximum PBDE level obtained in the muscle of eel was 17 mg/kg fat. The analyds indicated that there was at least one local source of pollution along the River Haggan. 2,2' ,4,4'-TeBDE was the most abundant PBDE-component. In most samples, this compound accounted for 70-80% of total PBDE. The mean concentration of PBDE ranged from ND (0.1 mg/kg) to 88 mg/kg fat. Eel caught upstream, midstream, and in the Klosterfjorden bay contained mean concentrations of ND (0.1 mg/kg), 4.3-16, and 0.9-1.4 mg PBDE/kg fat, respectively (Andersson & Blomkvist, 1981). Muscle tissue from bream, pike, and perch from the Viskan and Haggan rivers in Sweden contained levels of 2,2',4,4'-TeBDE of between 1 and 23 mg/kg (on a fat basis). Perch from the Viskan river had the highest levels (23 mg/kg) (Sellstrom et al., 1990b). A method for the multiresidue analysis of organic pollutants was applied to pooled muscle samples of 35 fresh water whitefish (Coregonus sp.), 15 samples of arctic char (Salvelinus a/pinus), and a total of 260 samples of herring (Clupea harengus), collected at different places in Sweden during the period 1986-87. The average concentrations of 2,2',4,4'-tetrabromodiphenyl ether for whitefish, arctic char, and herring were 15, 400, and 59-450 ~-tg/kg lipid, respectively (Jansson et al., 1993). Bream, pike, perch, and trout from Swedish waters contained 250-750, 2000-6500, 2200-24 000, and 120-460 1-tg 2,2',4,4'­ TeBDE/kg lipid, respectively. These samples were from back­ ground and industrialized areas (Sellstrom et al., 1993a). Pike samples from a Swedish lake indicated a 4-fold increase in the same isomer from 1974 to 1991 (Sellstrom et al., 1993b).

5.1.3 Birds

Jansson et al. (1987) analysed pectoral muscle tissue of adult guillemot (Uria aalge) nestling and wintering in the Baltic Sea, adult birds of the same species nestling and wintering in the North Sea, and adult guiiiemot collected at Spitzbergen. The pectoral muscle of a single, adult, white tailed sea eagle (Haliaetus

227 EHC 162: Brominated dipheny/ ethers

albicilla) from the Baltic Sea was also analysed. The concentrations of polybrominated diphenyl ethers (PBDE), calculated as Bromkal 70-5D, in the muscle of the guillemots of the Baltic, North Sea, and Spitzbergen were 370, 80 and 130 1-tg/kg, respectively, and that for the Baltic eagle, 350 ~-tglkg on a fat basis. The chromatographic pattern of the PBDE was similar to that of the Bromkal 70-5 product used as a reference substance. A method for multiresidue analysis was applied to pooled muscle samples of 35 osprey (Pandion haliaetus), collected in Sweden in the period 1982-86. The average concentration of 2,2'4,4'-tetrabromodiphenyl ether in osprey was 1800 ~-tg/kg lipid (Jansson et al., 1993). A 10-fold increase in 2,2' ,4,4'-TeBDE has been indicated in guillemot eggs from the Baltic Sea (Sell strom et al., 1993a) (Table 29).

5. 1.4 Aquatic mammals

Blubber samples of harbour seals (Phoca vitulina), collected in the southern Baltic Sea and the Kattegat, and a ringed seal (Pusa hispida), collected at Spitzbergen, were analysed by Jansson et al. (1987). The concentrations of PBDE were 90, 10, and 40 ~-tglkg, on a fat basis, respectively. The chromatographic pattern of the PBDE was similar to that of the Bromkal 70-5 product used as a reference substance. Sellstrom et al. (1990b) reported a concentration of 730 1-tg PBDE/kg, on a fat basis, in a grey seal from the Baltic Sea. Seven pooled samples of blubber of ringed seal (Pusa hispida), collected in 1981, and 8 pooled samples of blubber of grey seals (Halichoerus grypus), collected in Sweden in 1979-85, were analysed using a multiresidue analytical method. The average concentrations of 2,2'4,4'-tetrabromodiphenyl ether were 47 and 650 ~-tglkg lipid, respectively (Jansson et al., 1993).

228 Tetrabromodiphenyl ether

Table 29. Average concentrations of 2,2'.4.4'-TeBDE in guillemot eggs from the Baltic Sea (in ,ug/kg lipid)"

Sampling year 2,2'.4.4'-TeBDE

1970 130

1974 170

1975 130

1976 600

1979 640

1982 820

1983 880

1986 1200

1987 650

1989 1500

"From: Sellstrom et al. (1993a).

5.1.5 Terrestrial mammals

Multiresidue analysis of organic pollutants was applied to pooled muscle samples of 15 rabbits (Oryctolagus cuniculus), 13 samples of moose (Alces alces), and 31 samples of suet of reindeer (Rangifer tarandus). The samples were collected in Sweden in the period 1985-86. The average concentrations of 2,2' ,4,4'­ tetrabromodiphenyl ether were < 2, 0.82, 0.17 p.g/kg lipid, for rabbit, moose, and reindeer, respectively (Jansson et al., 1993).

5.2 General population exposure

No measurements are available of human exposure to TeBDE. In Sweden, the major human exposure is via fish-related food, and the levels of TeBDE in fish may be used to estimate this route of exposure. Normal fish intake in Sweden is about 30 g/day, and, if herring is used as a model fish, this wiii give an estimated intake of approximately 0.3 p.g TeBDE/person per day (Personal Communication, Jansson).

No data are available on occupational exposure during manufacture, formulation, or use.

229 6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

The half-life of pentabromodiphenyl ether (Bromkal 70) was investigated in the perirenal fat of groups of 3 male and 3 female Wistar rats (weight 160-180 g) following a single dose of 300 mg/kg body weight in peanut oil. Animals from the groups were killed on days 1, 2, 3, 4, and 7, and then once a week for 10 weeks. Perirenal fat was collected and analysed. The half-life of TeBDE was 19.1 days for male rats and 29.9 days for female rats (Meyerinck et al., 1990).

230 TRIBROMODIPHENYL ETHER

1. SUMMARY. EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

Tribromodiphenyl ether is not manufactured or used.

No data are available on the following topics:

• Environmental transport, distribution, and transformation • Kinetics and metabolism in laboratory animals and humans • Effects on laboratory mammals and in vitro test systems • Effects on humans • Effects on other organisms in the laboratory and field • Previous evaluations by international bodies.

1.1 Summary and evaluation

There is no database on which to make an evaluation.

1.2 Recommendations

Levels of contamination of commercial products with tribromodiphenyl ether should be minimized to avoid contamination of the environment and the exposure of humans. Use of such commercial products leading to environmental contamination should be avoided.

233 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2.1 Identity

Chemical structure 6' 6

5

4' 4

Chemical formula: Relative molecular mass 407.1 Common names tribromodiphenyl ether (TrBDE); tribromodiphenyl oxide CAS registry number 49690-94-0 CAS name 1, 1'-oxybis-tribromo-benzene

On the basis of the chemical structure, there are 24 possible isomers of tribromodiphenyl ether.

2.2 Physical and chemical properties

Vapour pressure 4.70-4.95 Pa at 25 oc n-Octanol/water partition coefficient (log Pow) 5.47-5.58

234 Tribromodiphenyl ether

From: US EPA (1984, 1986); Watanabe (1987c); Pijnenburg & Everts (1991).

2.3 Analytical methods

No specific data are available (see General Introduction, section 2.1 and Table 2).

235 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

Tribromodiphenyl ether has not been reported to occur naturally (see General Introduction, section 1.1).

236 4. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

4.1 Environmental levels

4.1.1 Birds

Stafford (1983) found tribromodiphenyl ether (TrBDE) in the eggs of the fish-eating bird, the black skimmer (Rynchos niger), collected from various nesting sites in Texas and Louisiana in the period 1980-81. The residues were not quantified.

237

DIBROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS, AND RECOMMENDATIONS

Dibromodiphenyl ether is not manufactured or used. No data are available on the following topics:

• Kinetics and metabolism in laboratory animals and humans • Effects on humans • Effects on other organisms in the laboratory and field • Previous evaluations by international bodies.

1.1 Summary and evaluation

There is no database on which to make an evaluation.

1.2 Recommendations

Contamination of commercial products with dibromodiphenyl ether should be minimized to avoid contamination of the environment and exposure of humans. Use of such commercial products leading to environmental contamination should be avoided.

241 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2. 1 Identity

Chemical structure: 6' 6

5

4' 4

Chemical formula: Relative molecular mass: 328.02 Common name: dibromodiphenyl ether (DiBDE) dibrcmodiphenyl oxide CAS registry number: 2050-47-7 Synonyms: bis(bromophenyl) ether, 1.1'-oxybis (bromo), benzene

On the basis of the chemical structure, there are 12 possible isomers of dibromodiphenyl ether, and p,p'-dibromodiphenyl ether is one of them.

2.2 Physical and chemical properties

p,p'-Dibromodiphenyl ether (DiBDE) is a crystalline compound.

242 Dibromodiphenyl ether

Melting point: 60.5 °C (58-60 °C) Boiling point: 338-340 oc Vapour pressure: 3.85-4.02 Pa at 25 oc Specific gravity: 1.8 (solution) Solubility: very soluble in benzene, soluble in alcohol, and ethyl ether n-Octanol/water partition coefficient (log pow): 5.03

From: US EPA (1984, 1986); Environment Agency Japan (1987); Pijnenburg & Everts (1991).

2.3 Analytical methods

No specific data are available (see General Introduction, section 2.1, and Table 2).

243 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

Dibromodiphenyl ether has not been reported to occur naturally (see General Introduction, section 1.1).

3.2 Anthropogenic sources

3. 2. 7 Production levels and processes

p,p '-Dibromodiphenyl ether is prepared from

p-phenoxyaniline by sequential treatment with HBr + NaN02 and

Br2 + HBr followed by warming in acetic acid (US EPA, 1986).

244 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

The in vitro microbial degradation of dibromodiphenyl ether was studied with a soil isolate, strain S93B1, identified as Pseudomonas cruciviae. After enrichment and isolation, the bacteria was cultivated in an agar-slant at 30 oc for 12-17 days and growth was determined. Strain S93B1 did not grow on DiBDE as the sole source of carbon (Takase et al., 1986).

245 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

5.1 Environmental levels

5.1.1 Water

In Japan, p,p'-dibromodiphenyl ether was not detected in 27 water samples (limit of determination 0.01-0.03 J.Lg/litre) in an environmental survey in 1984 (Environment Agency Japan, 1987).

5.1.2 Soil/sediment

In Japan, p,p'-dibromodiphenyl ether was not detected in 27 sediment samples (limit of determination 0.05-13 J.Lg/kg dry weight) in an environmental survey in 1984 (Environment Agency Japan, 1987).

5.1.3 Birds

Stafford (1983) found p,p '-dibromodiphenyl ether in eggs of the fish-eating bird, the black-skimmer (Rynchops niger), collected from various nesting sites in Texas and Louisiana in the period 1980-81. The residues were not quantified.

5.2 General population exposure

No data are available.

246 6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS

No data are available on the following topics: • Short-and long-term toxicity • Skin and eye irritation, sensitization • Reproductive toxicity, embryotoxicity, teratogenicity, mutagenicity, and carcinogenicity.

6.1 Single exposure

The acute intraperitoneal LD50 in mice is 125 mg/kg body weight (US EPA, 1984).

6.2 Other special studies

6.2.1 Liver

Carlson (1980a) and Kociba (undated) tested p,p'-dibromo­ diphenyl ether in a dose of 0.1 mmol/kg body weight per day, by gavage, in corn oil, in male Sprague Dawley rats (200-250 g) for 14 days. Twenty-four hours after the last (seventh) dose, increases in liver/body weight ratio, NADPH cytochrome c-reductase, and cytochrome P-450 were found.

247

MONOBROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

No data are available on the following topics: • Kinetics and metabolism in laboratory animals and humans • Effects on humans • Previous evaluations by international bodies.

1.1 Summary and evaluation

1. 1. 1 Physical and chemical properties

There are 3 possible isomers of monobromodiphenyl ether. p-Bromodiphenyl ether is a liquid at ambient temperature with a boiling point of 305-310 °C. Its solubility in water is calculated to be 48 mg/litre. The log n-octanol water partition coefficient is between 4 and 5. Vapour pressure at 20 oc is 0.0015 mmHg.

1.1.2 Production and uses

MBDE is not used as a flame retardant. A report of production appeared in 1977, but the use is unknown.

1. 1.3 Environmental transport, distribution, and transformation

The half-life of volatilization from water is in the range of hundreds of days. MBDE did not significantly biodegrade in a 7-day culture with microorganisms from domestic waste water, but it has been reported to degrade by 95% in activated sewage sludge. A single study showed a strain of soil bacteria incapable of degrading MBDE as a sole carbon source.

251 EHC 162: Brominated diphenyl ethers

1.1.4 Environmental levels and human exposure

MBDE has been detected in surface water samples taken near industrial sites in the USA but was not found in a similar survey in Japan. It was also detected in soil water close to an industrial plant in the USA. MBDE has been detected in aquatic sediment and aquatic biota in the USA.

1.1.5 Kinetics and metabolism in laboratory animals and humans

No data are available.

1.1.6 Effects on laboratory mammals and in vitro test systems

MBDE is not teratogenic, but there are no data on the acute, short-term, or long-term toxicity of MBDE and therefore no evaluation can be made.

1. 1. 7 Effects on humans

No data are available.

1. 1.8 Effects on other organisms in the laboratory and field

A 96-h LC50 for bluegill sunfish has been reported at 4.9 mg/ litre with a no-observed-effect concentration at less than 2.8 mg/

litre. The 48-h LC50 for waterflea was 0.36 mg/litre with a NOEC at less than 0.046 mgllitre.

1.2 Conclusions and recommendations

Monobromodiphenyl ether does not have any flame retardant properties. It can accumulate in organisms in the environment and has been detected in different environmental compartments. There is some evidence that it can be biodegraded. The limited information means that conclusions concerning exposure levels and effects on the general population and organisms in the environment cannot be reached. There is no toxicological data base to support its use.

252 Monobromodipheny/ ether

Uses leading to environmental contamination should be avoided.

253 2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2. 1 Identity

Chemical structure:

6 0 6' 5 5'

4' Br 3'

Chemical formula: Relative molecular mass: Common names: monobromodiphenyl ether (MBDE) mono bromodiphenyl oxide CAS registry number: 101-55-3 CAS name: bromo-4-phenoxybenzene Synonyms: bromophenylphenyl ether, bromodiphenyl ether, bromophenyl ether, bromophenoxybenzene Trade names: HSDB 2747; NSC

On the basis of the chemical structure, there are 3 possible isomers of monobromodiphenyl ether. p-Monobromodiphenyl ether is one of them.

254 Monobromodiphenyl ether

2.2 Physical and chemical properties

p-Bromodiphenyl ether is a liquid at common ambient temperatures.

Melting point: 18.72 oc Boiling point: 310.14 oc (305 °C) Vapour pressure at 20°C: 0.0015 mmHg Specific gravity: 1.449 (1.4208 at 20 °C) Refractive index, n 20/D: 1.607 Flash point: > 230 °F Solubility at 25 oc: 4.8 mg/litre water (calculated), soluble in ethyl ether n-Octanol/water partition coefficient (log Pow): 4.28 (4.08-4.94)

From: US EPA (1984, 1986).

2.3 Analytical methods

p-Monobromodiphenyl ether (MBDE) can be determined by the standard US EPA method 611-Haloethers. Chromatographic conditions are described in US EPA (1986). The limit of determination in municipal and industrial waste waters is 2.3 J.Lg/litre. Zogorski (1984) reported a limit of determination of 0.01 J.Lg/litre using a gas chromatograph equipped with an electron capture detector. McMahon (1983) applied GC-MS (US EPA method 625) using a halide specific detector. Gurka et al. (1982) used GC/Fourier transform infrared spectroscopy to detect p-monobromodiphenyl ether (see also General Introduction, section 2.1 and Table 2).

255 3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

Monobromodiphenyl ether has not been reported to occur naturally (see General Introduction, section 1.1).

3.2 Anthropogenic sources

3. 2. 1 Production levels and processes

p-Monobromodiphenyl ether is prepared by brominating

diphenyl ether with Br2 at 95-100 oc in carbon tetrachloride (US EPA, 1986). The production range (includes importation volumes) statistics from the 1977 TSCA Inventory were up to 450 kg of p-monobromodiphenyl ether (US EPA, 1986).

3.2.2 Uses

No data are available.

256 4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

4.1 Transport and distribution between media

The half-life of p-monobromodiphenyl ether with respect to volatilization has been estimated to be within the range of hundreds of days (MacKay & Leinonen, 1975). In contrast, by analogy to p-monochlorodiphenyl, Callahan et al. (1979) estimated the half-life of p-monobromodiphenyl ether to be 10 h. However, sorption of the agent by organic material in water will prolong its evaporative half-life in natural bodies of water. This value should be considered a minimum.

4.2 Biotransformation

4. 2. 1 Biodegradation

p-Monobromodiphenyl ether was not significantly biodegradable in a 7-day static-culture flask-screening procedure of Bunch and Chambers utilizing biochemical oxygen demand (BOD) dilution water containing 5 mg of yeast extract/litre, as the synthetic medium; 5 and 10 mg/litre concentrations of the test compound, a 7-day static incubation of 25 oc in the dark, followed by three weekly subcultures (totalling 28 days of incubation), and incorporating settled domestic waste water as microbial inoculum. At a test compound concentration of 5 mg/litre, only 2 out of 4 cultures showed any biodegradation in 7 days (19 and 36%), and, at a concentration of 10 mg/litre, only one out of 4 showed biodegradation (19%) (Tabak et al., 1981). p-Monobromodiphenyl ether was not able to support the growth of Alcaligenes BM2, a strain of soil bacteria capable of using PCB (dichloro-) mixtures as the sole source of carbon (Yagi & Sudo, 1980). However, p-monobromodiphenyl ether was reported to be 95% biodegradable when introduced as a pollutant (360 J.tgllitre) in a full-scale activated sludge treatment system (US EPA, 1986).

257 EHC 162: Brominated diphenyl ethers

The in vitro microbial degradation of p-monobromodiphenyl ether was studied with a soil isolate, strain S93B 1, identified as Pseudomonas crucivae. After enrichment and isolation, the bacteria were cultivated in an agar-slant at 30 oc for 12-17 days and growth was determined. Strain S93B1 did not grow on the biphenyl ether as the sole source of carbon (fakase et a!., 1986).

258 5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

No data are available on general population exposure or on occupational exposure during manufacture, formulation, or use.

5.1 Environmental levels

5.1.1 Water

According to US EPA (1986), there are monitoring data for p-monobromodiphenyl ether in water in the USA. The mean concentration was 0.2 mg/litre (range 0-202.7 mg/litre, 2193 listings) in water. Most of these listings concerned river water samples taken near industrial sites. Only a few groundwater and community drinking-water samples were included (no further details were available). Plumb (1991) reported the presence of p-monobromodiphenyl ether in groundwater from only 1 out of 479 disposal sites that were analysed in the USA. In Japan, p-monobromodiphenyl ether was not detected in 27 water samples (limit of determination 0.15-0.5 ~tg/litre) in an environmental survey in 1984 (Environment Agency Japan, 1987).

5. 1.2 Soil/sediment

According to US EPA (1986), there are numerous US monitoring data for p-monobromodiphenyl ether in sediments. The mean concentration was 3.5 mg/kg (range 0-380 mg/kg, 585 listings) (no further details are available). In Japan, p-monobromodiphenyl ether was not detected in 27 sediment samples (limit of determination 2.5-120 ~tglkg dry weight) in an environmental survey in 1984 (Environment Agency Japan, 1987).

259 EHC 162: Brominated diphenylethers

5. 1.3 Aquatic organisms

According to US EPA (1986) there are numerous US monitoring data for p-monobromodiphenyl ether in tissue from aquatic organisms. The concentrations were 2.0 mg/kg (range 0- 70.0 mg/kg, 346 listings) (no further details are available).

260 6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS

No data are available on the following topics:

• Single exposure • Short-term exposure • Long-term exposure • Skin and eye irritation; sensitization • Mutagenicity and related endpoints.

6.1 Reproductive toxicity, embryotoxicity, and teratogenicity

Outbred Swiss (CD-1) mice (age 60 days) were treated with p­ monobromodiphenyl ether (95% ). There were 20 and 21 mice respectively in these treatment groups and 51 and 55 mice in untreated and vehicle control (1 ml corn oil/kg) groups, respectively. Two females per group were mated per male, until a copulation plug was found, or for maximum 5 days. MBDE in corn oil was administered by gavage in dose levels of 0, 100 or 1.000 mg/kg body weight/day, from day 5 up to day 14 of gestation. Pups were counted and weighed (by litter) on postnatal days 1, 3, 5, 10 and 15; they were sexed and weaned on day 21 and autopsied on days 25 and 30 to determine gross abnormalities and the weights of Harderian glands, liver, and kidneys. No adverse effects on any of these parameters were observed (Francis, 1989).

6.2 Carcinogenicity

Theiss et al. (1977) tested p-monobromodiphenyl ether (MBDE) in a short-term screening assay: the strain A mouse pulmonary tumour assay. Four groups of 20 A/St male mice (6-8 weeks old) were given 24 intraperitoneal injections of tricaprylin (solvenH:ontrol), 23 i.p. injections of 40 mg (low-dose), 17

261 EHC 162: Brominated diphenyl ethers

InJections of 100 mg (mid-dose) and 18 injections of 200 mg MBDE/kg body weight (high-dose), three times per week. Total doses administered in the four groups were 0, 920, 1700, and 3600 mg/kg body weight, respectively. Twenty-four weeks after the first injection, the mice were sacrificed and the lungs examined. The number of lung tumours/mouse and survival rates of the treated animals were not significantly different from the control animals. The number of lung tumours/mouse were; control 0.39 ± 0.06; low-dose 0.18 ± 0.10, mid-dose 0.15 ± 0.10 and high-dose 0.31 ± 0.15. MBDE was negative in this pulmonary assay.

262 7. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD

The effects of acute exposure to p-monobromodiphenyl ether have been studied in several species of aquatic invertebrates and fish. The results are summarized in Table 30. The water flea (Daphnia magna), is more sensitive than fish to p-monobromo­ diphenyl ether (US EPA, 1984). In an early-life-stage (embryo-larval) test on fathead minnow, conducted with p-monobromodiphenyl ether, adverse effects on survival and growth were produced. The geometric mean of the highest no-effect level was 0.122 mg/litre (US EPA, 1984).

263 t\.) ~ Table 30. Acute toxic effects of p-monobromod1phenyl ether on aquatic organisms8

Spec1es Exposure Mean Effect Reference duration Method concentration (h) (mg/litre)

Rainbow trout 24 stat1c-aerated 5.0 stress observed Applegate et al. (1957) (Oncorhynchus mykissf

Bluegill sunfish 24 statlc·aerated 5.0 stress observed Applegate et al. (1957) (Lepomis macrochirus}

Bluegill sunfish 24 statiC 50.9c LCso US EPA (1978); (Lepomis macrochirus} Buccafusco et al. (1981)

48 static 9.62 LC 50 US EPA ( 1978) 72 static 4.94 LC 50 US EPA ( 1978)

96 static 4.94 LC 50 US EPA (1978) 96 statiC < 2.80 no effect US EPA (1978)

Sea lamprey 24 static-aerated 5.0 stress observed Applegate et al. (1957) (Petromyzon marinus}

Water flea 24 statiC 0.46 LC 50 US EPA (1978); LeBlanc (1980) (Daphnia magna} 48 static 0.36 LC 50 US EPA (1978); LeBlanc (1980) 48 statiC < 0.046 no effect US EPA (1978)

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Thoma H & Hutzinger 0 (1987) Pyrolysis and GC/MS-ana!ysis of brominated flame retardants in on-line operation. Chemopshere, 16(6): 1353-1360.

Thoma H & Hutzinger 0 (1989) Pyrolysis and GC/MS-analysis of brominated flame retardants in on-line operation. Chemosphere, 18(5): 1047-1050.

Thoma H, Hauschulz G, Knorr E, & Hutzinger 0 (1987a) Polybrominated dibenzofurans (PBDF) and dibenzodioxins (PBDD) from the pyrolysis of neat brominated diphenylethers, biphenyls and plastic mixtures of these compounds. Chemosphere, 16(1): 277-285.

Thoma H, Hauschulz G, & Hutzinger 0 (1987b) PVC-induced chlorine-bromine

278 References

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Timmons LL & Brown RD (1988) Analysis of the brominated fire retardant decabromdiphenyloxide for low and trace levels impurities. Chemosphere, 17: 217-234.

UK DOE (1992) Risk benefit analysis of hazardous chemicals. London, UK Department of Environment.

Ulsamer AG, Osterberg RE, & McLaughlin J Jr (1980) Flame retardant chemicals in textiles. Clin Toxicol, 17(1): 101-131.

UMWELTBUNDESAMT (1989) Status report: Polybrominated dibenzodioxins and polybrominated dibenzofurans. Berlin.

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US EPA (1984) Health and environmental effects profile for brominated diphenyl ethers. Cincinnati, Ohio, US Environmental Protection Agency, Environmental Criteria and Assessment Office (EPA/600/X-84/133).

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Vinci TM & Craig DK (1988) Characterization of fume components generated during the extrusion of flame-retarded polyester resins. Columbus, Ohio, Battelle (Unpublished report to GE Plastics, Mt. Vernon, Indiana, submitted to WHO by BFRIP).

Von Meyerinck L, Hufnagel B, Schmoldt A, & Benthe HF (1990) Induction of rat liver microsomal cytochrome P-450 by the pentabromodiphenyl ether Bromkal 70 and half lives of its components in the adipose tissue. Toxicology, 61: 259-274.

279 EHC 162: Brominated diphenyl ethers

Walsh GE, Yoder MJ, McCiaughlin LL, & Lores EM (1987) Responses of marine unicellular algae to brominated organic compounds in six growth media. Ecotoxicol Environ Saf, 14: 215-222.

Watanabe I (1987) Text from undated slide presentation.

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Zweidinger RA, Cooper SD, Erickson MD, Michael LC, & Pellizzari ED (1977) Sampling and analysis for semivolatile brominated organics in ambient air. In: Schuetzle D ed. Monitoring toxic substances. Washington, DC, American Chemical Society, pp 217-231 (ACS Symposium Series No. 94).

Zweidinger RA, Cooper SD, & Pellizzari ED (1978) Identification and quantitation of brominated fire retardants. In: Measurement of organic pollutants in water and waste water. Symposium of the American Society for Testing and Materials, Denver, Colorado, 19-20 June 1978. Philadelphia, Pennsylvania, American Society for Testing and Materials, pp 234-250 (ASTM Technical Publication No. 686).

281

RESUME ET EVALUATION, CONCLUSIONS ET RECOMMANDATIONS

DECABROMODIPHENYLETHER

1 Resume et evaluation

1. 1 ldentite, proprietes physiques et chimiques

Le DeBDE du commerce se caracterise par une purete de 97 a 98%, et une teneur en nona- et/ou octabromodiphenylethers de 0,3 a 3,0%. Le nonabromodiphenylether (NBDE) en est l'impurete principale. Contrairement aux autres polybromo-diphenylethers, le DeBDE n'a qu'un isomere. Le point de fusion du DeBDE est d'environ 300 oc et il se decompose au dessus de 400 °C. Sa solubilite dans l'eau est de 20-30 llg/litre et le logarithme de son coefficient de partage n-octanol/eau est superieur a 5. Sa tension de vapeur est < 10-6 mmHg a 20°C.

1. 2 Production et usages

De to us les bromodiphenylethers (mono- a deca-) le decabromodiphenylether est, de par sa production et son usage, le plus important du point de vue commercial. On le produit depuis Ia fin des annees 70 a un degre de plus en plus eleve de purete. La production mondiale de DeBDE est d'environ 30 000 tonnes par an. On l'utiliSe comme retardateur de flamme dans de nombreuses matieres plastiques, notamment dans le polystyrene choc, ainsi que pour le traitement des tissus d'ameublement, ou encore des textiles utilises en sellerie automobile ou pour Ia confection detentes.

283 EHC 162: Brominated diphenylethers

1.3 Transport, distribution et transformation dans l'environnement

En solution dans des solvants organiques, le DeBDE subit une photod~composition sous !'influence du rayonnement ultra-violet ou de Ia lumiere solaire; cette r~action conduit ll. Ia formation de bromodipbenyl~thers moins substitu~ et de bromodibenzofuranes. Cette photod~composition se produit ~galement, quoique dans une moindre mesure, en solution aqueuse, sous !'action du rayonnement solaire; on ne retrouve plus alors d'homologues inf~rieurs du DeBDE ni de bromodibenzofuranes.

Les quantit~s de DeBDE que !'on peut extraire des polymeres sont inf~rieures ll. Ia limite de d~tection ou tres proches de cette limite, selon le type de polymere et le solvant d'extraction.

Du fait que sa solubilit~ dans l'eau et sa tension de vapeur sont tres faibles, le DeBDE est vraisemblablement transport~ essentiellement par adsorption sur des particules. II est persistant et s'accumule probablement dans les s~iments et le sol.

On en dispose d'aucune donn~e sur sa biodisponibilit~ ll. partir des s~iments et du sol. Une ~tude sur des truites arc-en-ciel n'a pas r~v~l~ de bioaccumulation dans Ia chair, Ia peau ou les visceres de ces poissons, sur une p~riode de 48 heures. II est improbable que le DeBDE subisse une bioaccumulation en raison de sa masse mol~culaire relative ~lev~e. Les rebuts qui contiennent du DeBDE commercial finissent dans les d~charges control~es ou les incin~rateurs. II se peut que du DeBDE s'~chappe de ces d~charges par lessivage. Le brfilage sur les decharges ou une incin~ration inefficace peuvent conduire ll. Ia formation de polybromodibenzofuranes (PBDF) et d'un m~lange d'halog~nodibenzofuranes et d'halog~nodibenzodioxines. Les produits qui contiennent du DeBDE commercial peuvent contribuer ll. ces ~missions.

La pyrolyse, en pr~sence d'oxygene, de DeBDE commercial et de polymeres contenant de ce produit (polystyrene choc, PBT, polypropylene industriel) produit des polybromodibenzofuranes et en moindre quantit~s. des polybromodibenzodioxines. C'est aux temp~ratures de 400 ll. 500°C que les PBDF sont produits en quantit~s maximales mais ils peuvent ~galement se former ll. des

temp~ratures all ant jusqu 'll. 800°C et Sb20 3 en catalytise Ia formation.

284 Resume et evaluation, conclusions et recommandations

La formation des PBDF et des PBDD ainsi que leurs proportions respectives, dependent de Ia temperature, de Ia teneur en oxygene et de Ia duree de Ia pyrolyse. En l'absence d'oxygene, il s.e forme principalement des polybromobenzenes et des polybromonaphtalenes.

1.4 Concentrations dans l'environnement et exposition humaine

On a trouve du DeBDE dans l'air a proximite d'unites de 3 production, a des concentrations allant jusqu'a 25 p.g/m . En revanche, on n'a pas decele de DeBDE dans des echantillons d'eau preleves au Japon entre 1977 et 1991. Cependant, on en a trouve dans des sediments de rivieres, egalement preleves au Japon au cours de Ia m~me periode, a des deconcentrations allant jusqu'a environ 12 mg/kg de poids sec. On a egalement decele Ia presence Gusqu'a 1 g/kg) de DeBDE dans des sediments de cours d'eau aux Etats-Unis, a proximite d'une unite de production. On n'a pas decele de DeBDE dans des echantillons de poissons recueillis au J apon, mais, dans un echantillon de moules on en a trouve a des teneurs juste superieures au seuil de detection. Le produit n'a pas ete decele dans des echantillons de tissus adipeux humains preleves au Japon; en revanche, aux Etats-Unis, on en a trouve dans trois echantillons sur cinq du m~me type de tissus. Au cours de Ia production de DeBDE et de son adjonction aux polymeres, il peut y avoir exposition humaine. En revanche, cette exposition est negligeable pour Ia population generale. En cherchant a determiner !'exposition professionnelle aux produits de decomposition du DeBDE lors de sa fabrication et de son incorporation par extrusion a des polymeres, on a constate Ia presence de fortes concentrations de PBDF dans des echantillons d'air preleves au niveau de Ia filiere de l'extrudeuse. Les concentrations etaient moindres dans !'air de !'atelier. Des PBDF ont ete egalement retrouves dans des echantillons obtenus lors de l'essuyage. Moyennant une bonne technique de travail, on peut reduire I' exposition professionnelle aux PBDF. L'exposition de Ia population generale aux PBDF presents comme impuretes dans des polymeres contenant des retardateurs de flamme, est vraisemblablement negligeable.

285 EHC 162: Brominated diphenyl ethers

1.5 Cim§tique et m8tabolisme chez les animaux de laboratoire et l'homme

Le DeBDE est faiblement resorbe dans les voies digestives et apres injection, il est rapidement excrete. D'apres les resultats d'etudes de metabolisme chez le rat, au moyen de DeBDE marque au 14C, Ia demi-vie d'elimination de ce compose serait inferieure a 24 heures et Ia principale voie d'elimination apres ingestion, serait Ia voie fecale. On n'a pas constate Ia presence d'une activite appreciable de 14C (moins de 1%) dans !'urine ou !'air expire. Des rats a qui l'on avait administre pendant des periodes allant jusqu'a deux ans, une dose quotidienne de 0,1 mg/kg de poids corporel de ce compose, n 'ont presente aucun accumulation de DeBDE dans leur serum, leurs reins, leurs muscles ou leurs testicules, d'apres le dosage du brome total. L'accumulation du brome dans le foie a atteint un palier au bout de 30 jours et !'elimination s'est effectuee dans les 10 jours suivants le traitement. Apres 180 jours, Ia concentration de brome dans le foie n'etait pas plus elevee chez les rats traites que chez les rats temoins. Dans les tissus adipeux, on a note une faible accumulation de brome total, qui a subsiste apres 90 jours de nourriture sans DeBDE; on ignore quelle est Ia nature du "brome" retenu. Etant donne que le DeBDE ne representait que 77% du melange commercial utilise, ce "brome" pourrait provenir du NBDE ou de I'OBDE.

1. 6 Effets sur les mammiferes de laboratoire et les systemes d'8preuve in vitro

Pour les animaux de laboratoire, Ia toxicite aigue du DeBDE est faible. Le produit n'est pas irritant pour Ia peau ou les yeux des lapins. II ne provoque pas de chloracne sur Ia peau des lapins et n'a pas d'effet sensibilisateur sur Ia peau humaine. Les produits de combustion du polystyrene contenant un

retardateur de tlamme a base de DeBDE et de Sb20 3 ont ete etudies afin d'en determiner Ia toxicite aigue et Ia comedogenicite. Chez le

rat, Ia DL50 par voie orale de Ia suie et du residu de carbonisation etait > 2000 mg/kg de poids corpore!.

286 ResumtJ et ~valuation, conclusions et recommandations

Lors d'etudes de toxicite a long terme effectuees sur des rats et des souris, du DeB De (purete > 97%) a ete administre aux animaux mele a leur nourriture aux doses de 100 g/kg de nourriture (4 semaines) ou 50 g/kg (13 semaines, soit l'equivalent de 2500 mg/kg de poids corporel en ce qui concerne le rat) sans produire d'effets nocifs. Une etude de reproduction portant sur une generation de rats n'a pas revele d'effets nocifs aux doses de 100 mg/kg de poids corporel. Le DeBDE n'a pas provoque d'effets teratogenes chez des foetus de rats ayant re~,;u une dose de 100 mg/kg de poids corporel. A Ia dose de 1000 mg/kg de poids corporel, on a observe des malformations, par exemple un retard d'ossification. Soumis a un certain nombre d'epreuves, le DeBDE ne s'est pas revele mutagene. Lors d'une etude de cancerogenicite sur des rats et des souris, du DeBDE (purete 94-99%) a ete administre, mele a leur nourriture, a des doses allant jusqu'a 50 g/kg. On a observe une augmentation dans !'incidence des adenomes (mais pas des carcinomes) au niveau du foie chez les rats males qui en avaient re~,;u 25 g/kg et chez les femelles qui en avaient recu 50 g/kg. Chez les souris miHes, on a observe une augmentation de !'incidence des adenomes et/ou des carcinomes hepatocellulaires (les deux ensemble) a Ia dose de 25 g/kg et une augmentation des adenomes et des cancers (les deux ensemble) medullaires de Ia thyro'ide a ces deux doses. Chez les souris femelles, on n'a pas releve d'augmentation dans !'incidence des tumeurs. C'est uniquement aux doses de 25 a 50 g de DeBDE/kg de nourriture que chez les rats males et femelles d'une part, et chez les souris males d'autre part, on a constate !'existence de signes equivoques de cancerogenicite. Etant donne que les resultats de toutes les epreuves de mutagenicite sont restes negatifs, on peut en conclure que le DeBDE n'est pas un cancerogene genotoxique. Le CIRC (1990) est parvenu a Ia conclusion que les preuves d'une cancerogenicite du DeBDE chez les anin.aux de laboratoire sont limitees. Du fait des tres fortes doses utilisees dans ces etudes, de I' absence de genotoxicite et des elements de preuve tres minimes en faveur d'une cancerogenicite de ce compose, on peut conclure que le DeBDE, aux taux d'exposition actuels, ne presente pas de risque cancerogene pour I 'homme.

287 EHC 162: Brominated diphenyl ethers

1. 7 Effets sur l'homme

Chez des sujets humains exposes a du DeBDE lors d'une epreuve de sensibilisation, on n'a note aucun signe de sensibilisation cutanee. Une etude de morbidite sur des ouvriers qui procedaient a )'extrusion de polybutylene-terephtalate contenant du DeBDE (avec par consequent un risque potentiel d'exposition aux PBDD et aux PBDF pendant 13 ans) n'a pas revele Ie moindre effet deletere, malgre Ia presence dans leur sang de 2,3,7,8-TeBDF et de 2,3,7,8- TeBDD. Les etudes immunologiques effectuees ont montre que le systeme immunitaire des personnes exposees n'avait pas souffert au cours de ces 13 annees.

1.8 Effets sur les autres etres vivants au laboratoire et dans leur milieu nature/

La CE50 relative a Ia croissance de trois algues marines unicellulaires s'est revelee superieure a 1 mg de DeBDE par litre. On ne dispose d'aucune autre information concernant les effets du DeBDE sur Ies autres etres vivants au laboratoire ou dans leur milieu naturel.

2 Conclusions

2.1 DeBDE

Le DeBDE est largement utilise comme retardateur de flamme dans les polymeres. S'il entre en contact avec Ia population generale, c'est par l'intermediaire des produits fabriques a partir de ces polymeres. L'exposition est tres faible etant donne que Ie DeBDE n'est pas facile a extraire de ces polymeres. La toxicite aigue du DeBDE est tres faible et son absorption au niveau des voies digestives est minime. On peut done considerer comme insignifiant le risque que le DeBDE represente pour Ia population generale. C'est sous forme particulaire que le DeBDE peut donner lieu a une exposition professionnelle. En se premunissant contre Ies poussieres au cours de Ia fabrication et de I 'utilisation de ce produit, on peut efficacement en reduire les risques pour les travailleurs.

288 Resume et tJvaluation, conclusions et rfiCommandations

Le DeBDE est persistant et il se fixe sur les particules de matiere presentes dans l'environnement; il est vraisemblable qu'il s'accumule dans les sediments. En revanche, sa bioaccumulation est improbable. D'apres les donnees disponibles, Ia photodecomposition du DeBDE en milieu aqueux dans I'environnement ne conduit pas a Ia formation de diphenylethers bromes inferieurs ni de bromodibenzofuranes, mais on est mal renseigne sur Ia decomposition de ce compose dans d'autres milieux. On est egalement tres peu renseigne sur Ia toxicite du DeBDE pour les etres vivants dans leur milieu nature!.

2. 2 Produits de decomposition

II peut se former des PBDF et, dans une certaine mesure, des PBDD lorsque du DeBDE ou des produits qui en contiennent sont chauffes a 300-800 °C. II faut se preoccuper des dangers que ces produits pourraient representer,. Lorsqu'elle est correctement conduite, !'incineration n'entraine pas !'emission de quantites importantes de bromodioxines ou de bromodibenzofuranes. Si Ia combustion s'effectue dans des conditions non contr6lees, des PBDF et des PBDD peuvent prendre naissance en quantites indeterminees. Les risques qui pourraient en resulter pour l'homme et l'environnement seront etudies dans un prochain Critere d'hygiene de l'environnement sur les PBDF et les PBDD. On a observe Ia presence de PBDF dans le sang de travailleurs employes a Ia production de matieres plastiques contenant du DeBDE. Toutefois aucun effet delet~re sur leur sante n'a pu etre attribue a ce type d'exposition. Moyennant des techniques appropriees, il est possible d'eviter !'exposition des travailleurs aux PBDF.

3 Recommandations

3. 1 Recommandations generales

• II convient que les travailleurs qui sont employes a Ia fabrication de DeBDE et de produits qui en contiennent soient proteges contre toute exposition par !'application de

289 EHC 162: Brominated diphenylethers

mesures appropriees d 'hygiene industrielle, Ia surveillance de I' exposition professionnelle et des moyens techniques appropri~s. • II convient de minimiser I' exposition environnementale par un traitement appropri~ des effluents et des ~missions produits par les industries qui utilisent ce compos~ ou des produits qui en contiennent. Le rejet des d~chets industriels et des produits de consommation do it etre r~glement~ afin de r~uire au minimum Ia contamination de l'environnementpar ce compos~ persistant et ses produits de decomposition. • Les fabricants doivent faire en sorte que le DeBDE commercial contienne le minimum d'impuret~s, en utilisant pour cela les meilleures techniques existantes. Une puret~ d'au moins 97% est recommand~e.

• On ne doit proc~er a I'incin~ration qu'au moyen d'incin~rateurs convenables, qui fonctionnent toujours dans les conditions optimales. Le bn1lage des d~chets par tout autre moyen risque d'entralner Ia formation de PBDF et/ou de PBDD.

3. 2 Etudes a effectuer

• II conviendrait d'effectuer, sur les organismes appropri~s, des ~tudes sur Ia biodisponibilit~ et Ia toxicit~ du DeBDE li~ aux s~iments. • II importe d'assurer une surveillance permanente des concentrations dans l'environnement.

• La production de PBDF en situation r~elle d'incendie doit faire !'objet d'~tudes plus approfondies.

• II importe d'~tudier plus a fond Ia biod~composition dans I'environnement ainsi que Ia photodecomposition de ce compos~ dans des milieux autres que l'eau.

• II conviendrait d'~tudier des m~thodes pour le recyclage des polymeres contenant du DeBDE et leurs cons~quences.

• II faudrait valider les m~thodes d'analyse du DeBDE dans diverses matrices.

290 RfJsume et evaluation, conclusions et recommandations

NONABROMODIPHENYLETHER

Le nonabromodiphenylether n'est ni produit ni utilise. On ne dispose d'aucune donnee sur les points suivants: • Transport, distribution et transformation dans I' environnement • Concentrations dans I' environnement et exposition humaine • Cinetique et metabolisme chez les animaux de laboratoire et l'homme • Effets sur les mammiferes de laboratoire et les systemes d' epreuve in vitro • Effets sur I'homme • Effets sur les autres etres vivants au laboratoire et dans leur milieu nature! • Evaluations anterieures par des organismes inter­ nationaux.

1 Resume et evaluation

II n'existe aucune base de donnees sur laquelle se fonder pour une evaluation.

2 Recommandations

II importe de reduire au minimum le taux de contami-nation des retardateurs de tlamme bromes du commerce par le nonabromodiphenylether a fin d 'evittr une pollution de l'environnement et !'exposition humaine.

291 EHC 162: Brominated diphenyl ethers

OCT ABROMODIPHENYLETHER

L'octabromodiphenylether n'est ni fabrique ni utilise al'etat pur. On ne dispose d'aucune donnee sur les points suivants: • Cinetique et metabolisme chez les animaux de laboratoire et l'homme • Effets sur l'homme

• Effets sur les autres ~tres vivants au laboratoire et dans leur milieu nature) • Evaluations anterieures par des organismes inter­ nationaux.

1 Resume et evaluation

1. 1 Jdentit~ et proprieMs physiques et chimiques

L'OBDE du commerce se presente sous Ia forme d'un melange d'environ 11% de PeBDE/HxBDE, 44% de HpBDE, 31-35% d'OBDE, 10% de NBDE et 0,5% de DeBDE. D'apres Ia structure chimique, il y a the-oriquement 12 isomeres de l'OBDE et 24 isomeres de I 'HpBDE. Le point de fusion varie d'environ 80 oc a > 200 °C. La tension de vapeur est < 10·7 mmHg, Ia solubilite dans l'eau est faible et le logarithme du coefficient de partage n-octanolleau est > 5,5. Ces variations dans les proprietes physiques s'expliquent par des differences de composition des melanges etudies.

1.2 Production et usages

La consommation mondiale annuelle d'OBDE commercial est de 6000 tonnes, dont 70% sont utilises comme retardateurs de flamme dans les resines ABS qui servent a Ia fabrication d'ordinateurs et d'armoires de bureau. L'OBDE vient au second rang des retardateurs de flamme dans l'ordre d'utilisation.

292 Resume et 1Jvaluation, conclusions et recommandations

1.3 Transport, distribution et transformation dans l'environnement

On a trouve des constituants de l'OBDE du commerce dans des sediments aquatiques et des tissus adipeux humains. Certains de ces constituants aplus faible teneur en brome (HxBDE et PeBDE) ont ete observes dans des biotes. On n'a pas decele d'OBDE, mais on n'a cherche generalement nile HpBDE nile NBDE. Les constituants de l'OBDE commercial sont vraisemblablement persistants mais, lorsque le degre de substitution par le brome depasse 6, Ia bioaccumulation devient de plus en plus improbable. On a trouve chez Ia carpe un facteur de bioaccumulation de moins de 2 pour un OBDE commercial. La pyrolyse de l'OBDE commercial, soit tel que!, soit ajoute a

des polymeres comme retardateur de tlamme (avec ou sans Sb20 3) a 600 ac, produit des PBDF et, a beaucoup plus faibles concentrations, des PBDD. Le traitement des resines ABS avec de l'OBDE et du

Sb20 3 dans differentes conditions revele, que dans les conditions normales, il ne se forme que de faibles concentrations de PBDF. Lorsque les conditions sont mauvaises, les concentrations sont beaucoup plus elevees. En revanche, les concentrations de PBDD sont faibles dans les deux cas.

1.4 Concentrations dans l'environnement et exposition humaine

Dans des echantillons d'eau recueillis au Japon en 1987 et 1988, on n'a pas pu deceler d'OBDE ni de constituants de l'OBDE du commerce a plus faible teneur en brome. On a egalement analyse des echantillons de sediments et dans environ 2-6% d'entre eux, on a observe Ia presence d'OBDE ades concentrations de 8-22 J.tg/kg de· poids sec. Dans le sediment, on a egalement trouve des constituants moins substitues en brome. Chez des poissons captures au Japon en 1987 et en 1988, on n'a pas decele d'OBDE. Aux Etats-Unis d'Amerique, on a analyse en 1987 des echan­ tillons de tissus adipeux humains a Ia recherche de PBDF et de PBDD. Les echantillons provenaient de 865 prelevements associt~s de maniere a former 48 homologues composites. Ce schema d 'echantillonnage composite reposait sur 9 divisions censitaires et 3 groupes d'age. Dans ces echantillons, on a egalement constate Ia

293 EHC 162: Brominated dipheny/ ethers

presence de PBDE et les premiers resultats ont montre que de l'OBDE etait egalement present dans 60% des cas avec une concentration estimative all ant jusqu'a 8000 ng/kg.

1.5 Cint§tique et mtltabolisme chez les animaux de laboratoire et l'homme

Aucune donnee disponible.

1. 6 Effets sur les mammiferes de laboratoire et les systemes d'tlpreuve in vitro

L'OBDE du commerce presente une faible toxicite aigue pour les mammiferes de laboratoire. II n'est pas irritant pour Ia peau et ne provoque qu'une Iegere irritation oculaire chez le lapin. Lors d'etudes toxicologiques a court terme (respectivement 4 et 13 semaines), on a observe, chez des rats a qui l'on en avait administre dans leur nourriture a raison de 100 mg/kg, une augmentation du poids du foie et des alterations microscopiques caracterisees par Ia presence, dans Ia region centro- et medio­ lobulaire, de cellules parenchymateuses hypertrophiees contenant des structures granulaires. La gravite de ces lesions hepatiques etait plus marquee aux doses elevees, c'est-a-dire 1000 et 10 000 mg/kg de nourriture. En outre, on a observe une hyperplasie de Ia thyrofde. La teneur en brome total de ces tissus a augmente au cours de 1' etude pour diminuer ensuite lentement au cours de Ia periode de recuperation. Les anomalies hepatiques etaient reversibles. Lors d'une etude toxicologique par inhalation au cours de laquelle on a fait respirer de Ia poussiere micronisee d'OBDE aux animaux (8 h/jour, 14 jours de suite) on n'a pas observe d'effets a Ia concentration de 1,2 mg/m3 mais a celle de 12 mg/m\ on a observe des lesions hepatiques analogues a celles qui avaient ete decelees apres ingestion du produit. Chez le rat, des doses relativement faibles d'OBDE du commerce accroissent d'activite du cytochrome P-450 et induisent les enzymes des microsomes hepatiques, comme l'UDP-glucuronyl­ transferase et Ia benz[a]pyrene-hydroxylase. On a egalement constate que ce produit avait un effet porphyrinogene sur les cultures de cellules hepatiques d'embryon de poulet.

294 Resume et evaluation, conclusions et recommandations

L'etude du pouvoir teratogene de l'OBDE chez le rat a montre qu'a fortes doses (25,0 et 50,0 mg/kg de poids corpore!), ce produit provoquait des resorptions ou un retard d'ossification en differents points du squelette ainsi que des malformations foetales. Les malformations observees aux doses de 25 mg/kg de poids corpore! et au-deJa etaient tres vraisemblablement liees a Ia toxicite du produit pour Ia mere. Ces malformations n'ont pas ete observees aux doses inferieures ou egales a 15,0 mg/kg de poids corpore!. Chez le lapin, aucun signe d'activite teratogene n'a ete observe, en revanche on a constate une certaine foetotoxicite a Ia dose de 15 mg/kg de poids corpore! qui etait egalement toxique pour Ia mere. D'apres les etudes de teratogenicite, Ia dose sans effets nocifs observables est de 2,5 mg/kg de poids corpore!. Lors de deux etudes, l'une de 28 jours et !'autre de 90 jours, on a constate qu'une dose de 100 mg d'OBDE/kg de nourriture (soit !'equivalent de 5 mg/kg de poids corpore!) ne produisait que des effets minimes sur le foie. On n'a pas cherche a etablir Ia dose sans effets observables. Toutes les epreuves de mutagenicite: synthese non programmee de I' AD N, tests sur microorganismes in vitro et recherche d' echanges entre chromatides-soeurs sur cellules ovariennes de hamster chinois se sont revelees negatives. On ne possede aucune donnee resultant d'etudes de cancero­ genicite ou d'etudes a long terme.

1. 7 Effets sur /'homme

Aucune donnee disponible.

1.8 Effets sur les autres etres vivants au laboratoire et dans leur milieu nature/

Donnees minimales.

295 EHC 162: Brominated diphenyl ethers

2 Conclusions

2.1 OBDE

L'OBDE du commerce est un melange d'hexa-, d'hepta-, d'octa­ et de nonabromodiphenylethers, qui sont tous des composes remanents, en grande partie fixee aux sediments. L'OBDE est tres largement utilise comme retardateur de flamme dans les polymeres. II peut y avoir contact avec Ia population generale par l'intermectiaire de produits fabriques a partir de ces polymeres. II est peu probable qu'on puisse etre expose a de l'OBDE qui aurait ete extrait de ces polymeres. L'OBDE presente une faible toxicite aigue. On ne dispose d'aucune donnee sur sa fixation ou son elimination par l'organisme des mammiferes. II n'est ni teratogene ni mutagene. On ne dispose d'aucune donnee sur sa toxicite a long terme ni sur sa cancero­ genicite. On a releve Ia presence, dans des tissus adipeux humains, de plusieurs constituants de l'OBDE commercial. Pour Ia population dans son ensemble, le risque d'intoxication aigue est vraisemblablement faible. II n'est pas possible d'evaluer les risques d'une exposition a long terme en raison de !'absence d'etudes toxicologiques pertinentes. On ne dispose non plus d'aucune information qui permette de tirer des conclusions quant a !'exposition professionnelle a l'OBDE et a ses effets. Les donnees relatives a Ia toxicite de l'OBDE pour les etres vivants dans leur milieu nature! demeurent limitees. II est possible que les constituants peu substitues en brome du melange commercial subissent une bioaccumulation.

2. 2 Produits de decomposition

Lors du chauffage de l'OBDE ou de produits qui en contiennent a des temperatures de 400-800 °C, il peut se former des PBDF et, dans une certaine mesure, des PBDD. II importe de se preoccuper des dangers qui pourraient en resulter.

296 Resume et evaluation, conclusions et recommandations

II est improbable que Ia population generale soit exposee de fa~on notable aux impuretes de type PBDF, presentes dans les polymeres contenant des retardateurs de flamme. Moyennant une incineration dans les regles, il ne devrait pas y avoir d'emission importante de bromodioxines ni de bromofuranes. Le brOlage sans precautions de produits qui contiennent de I'OBDE du commerce, peut donner naissance ~ des PBDF et des PBDD en quantites indeterminees. Ce probleme et ses consequences pour Ia sante humaine et J'environnement, seront abordes dans un prochain Critere d'hygiene de l'environnement consacre aux PBDF et aux PBDD.

3 Recommandations

3. 1 Recommandations generales

• II convient d'utiliser Jes meilleurs techniques possibles pour la fabrication de l'OBDE du commerce, afin de rectuire au minimum Ia teneur en homologues hexabromes ou moins substitues, du fait de leur possibilite de bioaccumulation dans I' environnement.

• Les travailleurs qui sont employes ~ Ia fabrication de l'OBDE ou de produits qui en contiennent, doivent etre proteges contre !'exposition ~ ces derives par des mesures d 'hygiene industrielle, une surveillance de I' exposition professionnelle et des moyens techniques. • II convient de limiter au maximum Ia pollution de I' environnement grace ~ un traitement approprie des effluents et des emissions provenant d 'industries qui utilisent le compose ou des produits qui en contiennent. Le rejet de produits industriels et de produits de consommation devra etre reglemente de fa~on ~ rectuire au minimum Ia pollution de l'environnement par ces composes remanents et leurs produits de decomposition. • L'incineration de produits qui contiennent des retardateurs de flamme ~ base d'OBDE, ne doit s'effectuer que dans des incinerateurs appropries fonctionnant toujours dans des conditions optimales. Le brOlage par tout autre moyen risque de donner naissance ~des PBDF ou des PBDD.

297 EHC 162: Brominated diphenyl ethers

3. 2 Etudes a effectuer

Comme Ia base de donnees toxicologiques actuelle est insuffisante pour permettre d'evaluer les dangers que represente l'OBDE du commerce pour l'homme et l'environnement, et pour en faciliter !'utilisation, il est recommande d'entreprendre les etudes suivantes: • Etudes, sur des organismes appropries, relatives a Ia biodisponibilite eta l'ecotoxicite des constituants de l'OBDE du commerce lies aux sediments • Surveillance generalisee de Ia concentration des constituants de l'OBDE du commerce dans l'environnement • Etudes toxicologiques a long terme et etudes de cancero­ genicite portant sur I'OBDE du commerce • Surveillance de !'exposition professionnelle a l'OBDE du commerce • Poursuite des etudes sur Ia formation de PBDF dans des conditions reelles d, incend ie • Poursuite des etudes sur Ia biodecomposition et Ia photodecomposition environnementales dans des milieux non aqueux • Etudes de methodes de recyclage des polymeres contenant de l'OBDE et de ses consequences • Validation des methodes d'analyse de l'OBDE dans diverses matrices • Etudes sur Ia possibilite de migration a partir de divers types de polymeres.

HEPTABROMODIPHENYLETHER

L'heptabromodiphenylether n'est ni produit ni utilise.

298 Resume et evaluation, conclusions et recommandations

II n'existe pas de base de donnees relatives i'l. l'HpBDE pur sur laquelle fonder une evaluation.

On ne dispose d'aucune donnee sur les points suivants: • Cinetique et metabolisme chez les animaux de laboratoire et I 'homme • Effets sur I 'homme

• Effets sur les autres ~tres vivants au laboratoire et dans leur milieu nature! • Evaluations anterieures par des organismes inter­ nationaux. Du fait que l'HpBDE est le principal constituant de l'octabromodiphenylether du commerce, le resume, I' evaluation, les conclusions et les recommandations relatives a I 'OBDE du commerce, valent pour l'HpBDE "du commerce".

HEXABROMODIPHENYLETHER

L'hexabromodiphenylether n'est ni produit ni utilise mais il constitue une impurete des bromodiphenylethers du commerce. II convient d'en reduire Ia concentration au minimum afin d'eviter Ia contamination de l'environnement et !'exposition de l'homme. II n'existe pas de base de donnees sur laquelle fonder une evaluation. On ne dispose d'aucune donnee sur les points suivants: • Effets sur les mammiferes de laboratoire et les systemes d'epreuve in vitro • Effets sur l'homme • Effets sur les autres etres vivants au laboratoire et dans leur milieu nature!

299 EHC 162: Brominated diphenyl ethers

• Evaluations anterieures par des organismes inter­ nationaux.

PENTABROMODIPHENYLETHER

Le pentabromodiphenylether n'est ni produit ni utilise. On ne dispose d'aucune donnee sur les points suivants: • Effets sur l'homme • Effets sur les autres etres vivants au laboratoire et dans leur milieu nature! • Evaluations anterieures par des organismes inter­ nationaux.

1 Resume et evaluation

1. 1. 1 ldentite, proprietes physiques et chimiques

Le pentabromodiphenylether du commerce (PeBDE) est un melange de tetra-, penta- et hexabromodiphenylether. II contient approximativement 50-60% de PeBDE et 24-38% de TeBDE. D'apres Ia structure chimique, il existe theoriquement 46 isomeres du PeBDE et 42 isomeres du TeBDE. Les principaux constituants des produits du commerce semblent etre au nombre de 3, a savoir le 2,2' ,4,4' ,5'-PeBDE, le 2,2' ,4,4' -TeBDE et un analogue non identifie a 5 atomes de brome. Le point de fusion se situe entre -7 et -3 oc et le point d'ebullition au-deJa de 200 °C. La tension de vapeur est faible: < 10-7 mmHg et Ia solubilite dans l'eau, negligeable. Le logarithme du coefficient de partage n-octanol!eau est > 6.

1.2 Production et usage

Le PeBDE est utilise comme additif dans les resines epoxy, les resines phenoliques, les polyesters et le polyurethanne ainsi que les

300 RfJsumfi et {Jvaluation, conclusions et recommandations

textiles. Ia consommation mondiale est d'environ 4000 tonnes par an. C'est l'un des principaux bromodiphenylethers du commerce utilises comme retardateurs de tlamme.

1.3 Transport, distribution et transformation dans /'environnement

On trouve des constituants du PeBDE du commerce dans les biotes, les sediments et les boues d'egouts. II est vraisemblable que ces constituants soient remanents et qu' ils aient tendance a Ia bioaccumulation. C'est ainsi que !'on a trouve chez Ia carpe un facteur de bioconcentration de plus de 10 000. L'etude de Ia pyrolyse du PeBDE du commerce a montre qu'il se forme au cours de ce processus des PBDF et des PBDD. La temperature optimale de formation de ces composes se situe entre 700 et 800°C. Lorsque Ia pyrolyse du PeBDE s'effectue en !'absence d'oxygene, il y a formation de polybromobenzenes, de polybromophenols et de PBDF.

1.4 Concentrations dans /'environnement et exposition humaine

Dans des echantillons de sediments preleves au Japon dans des cours d'eau et des estuaires, on a releve des concentrations allant de 0 ( < 2 ~g/kg) jusqu'a 28 ~g/kg de poids sec de PeBDE. En Suede, les sediments de certains cours d'eau accusaient des concentrations allant jusqu'a 1200 ~g de 2,2' ,4,4' ,5'-PeBDE/kg. Des boues d'egouts, analysees en Suede, contenaient egalement de ce PeBDE. Des moules et poissons ont ete p"eieves aux fins d'analyse dans diverses zones littorales du Japon entre 1981 et 1985; dans deux echantillons de moules sur cinq, on a trouve des concentrations de PeBDE qui etaient respectivement egales a 0,4 et 2,8 J.lg/kg de poids humide. En revanche, dans le poisson, on n'a pas ctecele de PeBDE (limite de dosage < 0,2 ~g/kg). On a fait etat de concentrations de 1 ,9-22 ~g/kg de poids frais dans des echantillons de foie de morue provenant de Ia mer du Nord. En Suede, on a trouve des concentrations qui se situaient entre 7,2 et 64 J.lg de 2,2' ,4,4' ,5'­ PeBDE/kg de graisse dans des poissons d'eau douce du genre coregone et dans des harengs de differentes provenances.

301 EHC 162: Brominated diphenylethers

Du gras de phoque (Phoca hispida et phoque gris) preleve en Suede en 1979-85, s'est revele contenir des concentrations moyennes de 2,2',4,4',5'-PeBDE respectivement egales ll. 1,7 J.Lg et 40 J.Lg/kg de poids corporel. En Suede, dans un melange d'echantillons de muscles de lapins et d'elans ainsi que dans de Ia graisse de rognon de renne, on a constate, en 1985-86, Ia presence de concentrations respectivement egales ll. < 0,3 J.Lg, 0,64 J.Lg et 0,26 J.Lg de 2,2',4,4',5'-PeBDE/kg de graisse. Dans des echantillons de muscles de balbuzard, obtenus en Suede en 1982-86, on a note une concentration moyenne de 140 J.Lg de 2,2,' ,4,4' ,5' -PeBDE/kg de graisse. On a constate qu'au cours des dernieres decennies, Ia concentration de deux isomeres du PeBDE avait augmente d'un facteur 10 dans les oeufs de guillemots de Ia Baltique. On a egalement constate que Ia concentration de ces isomeres avait augmente d'un facteur 4 dans des brochets provenant d'un lac du sud de Ia Suede. L'analyse de sediments de la Baltique representatifs de plusieurs annees d'echantillonnage indique egalement qu'il y a eu une augmentation considerable de Ia pollution au cours de Ia derniere decennie. On est tres peu renseigne sur I' exposition humaine mais on peut estimer en gros, d'apres Ia consommation de poisson des suedois, que Ia population de ce pays absorbe individuellement environ 0,1 p.g de PeBDE par jour.

1.5 Cimltique et mlitabo/isme chez /es animaux de laboratoire et /'homme

La demi-vie du PeBDE n'a ete etudiee qu'au niveau de Ia graisse perirenale chez le rat. On a ainsi obtenu une valeur comprise entre 25 et 47 jours, en fonction du sexe de I' animal et du type d'isomere en cause.

7. 6 Effets sur les mammiferes delaboratoire et les systemes d'lipreuve in vitro

Le PeBDE du commerce presente une faible toxicite aigue par voie orale chez le rat; Ia toxicite par voie percutanee est egalement

302 Resum~ et evaluation, conclusions et recommandations

faible chez le lapin. En exposant pendant une breve durt~e des rats par Ia voie respiratoire et en instillant du PeBDE a des lapins dans le sac conjonctival, on n'a obtenu que des effets moderes et passagers. Des etudes toxicologiques a court terme sur des rats (4 semaines et 13 semaines respectivement) au cours desquelles du PeBDE a ete administre aux animaux a des concentrations de 100 mg/kg de nourriture, ont revele une augmentation du poids du foie et donne lieu a de legeres anomalies histologiques. Ces anomalies consistaient en une hypertrophie des cellules du parenchyme hepatique, qui avaient un aspect granulaire et contenaient des "inclusions rondes" eosinophiles. On a constate que Ia teneur en brome total du foie augmentait en fonction de Ia dose administree et restait elevee pendant des periodes pouvant aller jusqu'a 24 semaines. On a egalement observe une Iegere hyperplasie thyroldienne reversible. Apres administration par voie orale de doses quotidiennes de PeBDE ne depassant pas 0, 78 ~tmol/kg de poids corpore), on a observe l'induction des enzymes hepatiques et un accroissement de l'activite du cytochrome P-450 c. Les resultats des epreuves de teratogenicite et de mutagenicite se sont reveles negatifs. Aucune etude toxicologique a long terme ou etude de cancerogenicite n'a ete publiee.

1. 7 Effets sur /'homme

Pas de donnees disponibles.

1.8 Effets sur les autres etres vivants au laboratoire fJt dans leur milieu nature/

On ne dispose que d'un minimum de donnees.

2 Conclusions

2.1 PeBDE

Le PeBDE du commerce (melange de 24-38% de tetra-, 50-60% de penta- et 4-8% d 'hexabromodiphenylether) est remanent et il s'accumule chez les etres vivants dans leur milieu naturel.

303 EHC 162: Brominated dipheny/ ethers

Le PeBDE du commerce est largement utilise, incorpore a des polymeres, comme retardateur de flamme. Lorsqu'il entre en contact avec la population, c'est par l'intermediaire de produits fabriques a partir de ces polymeres. 11 est improbable qu'il puisse y avoir exposition apres extraction du produit de ces polymeres. 11 peut y avoir exposition de l'homme au PeBDE par l'intermediaire de la chaine alimentaire, etant donne que la substance a ete decelee chez divers animaux vivant dans leur milieu nature!, animaux qui servent de nourriture a l'homme, comme les poissons, les fruits de mer, etc. On constate depuis au moins deux decennies que les concentrations augmentent chez les poissons et les oiseaux de Suede. Le PeBDE du commerce presente une faible toxicite aigue. On ne possede aucune donnee sur la fixation et !'elimination de ce produit chez les mammiferes. On ne dispose pas non plus d'etudes sur la reproduction d'animaux exposes a cette substance, ni sur sa toxicite a long terme ou sa cancerogenicite. 11 n'est pas possible, a partir des donnees disponibles, d'evaluer le risque qu'il represente pour Ia population generale. On ne possede pas non plus de donnees qui permettent d'etablir le niveau d'exposition professionnelle ou de se prononcer sur les effets du PeBDE ?? du commerce. On ne dispose que de donnees limitees sur Ia toxicite du PeBDE du commerce pour les etres vivants dans leur milieu nature!.

2. 2 Produits de decomposition

Lorsqu'on chauffe du PeBDE ou des produits qui en contiennent a une temperature de 400-800 ac, il se forme des PBDF et, dans une certaine mesure, des PBDD. II faudra examiner les risques qui pourraient en decouler. 11 est peu probable que Ia population generale soit exposee de fa~on notable aux PBDF produits par des polymeres contenant du PeBDE comme retardateur de flamme. Si elle est convenablement effectuee, !'incineration n'entralne pas !'emission de quantites importantes de bromodioxines ou de bromofuranes. En revanche, le bn1lage inconsidere de produits qui en contiennent peut donner naissance a des quantites indeterminees de PBDF ou de PBDD. Dans un futur Critere d'hygiene de l'environnement consacre a ces deux

304 RlisumfJ et &valuation, conclusions et recommandations

substances, l'importance de ce probleme pour l'homme et I' environnement sera examinee.

3 Recommandations

3. 1 Recommandations generales

La remanence du PeBDE du commerce dans l'environnement et son accumulation dans les ~tres vivants militent contre l'utilisationde ce produit. Toutefois, s'ill'on continue~ l'utiliser, il faudra prendre les precautions suivantes:

• Les travailleurs qui sont employes ~ Ia production de PeBDE ou de polymeres qui en contiennent, doivent ~tre proteges contre toute exposition, par des mesures appropriees d'hygiene industrielle, Ia surveillance de I' exposition professionnelle et des moyens techniques convenables. • II convient de minimiser l'exposition environnementale par un traitement approprie des effluents et des emissions produits par les industries qui utilisent ce compose ou des produits qui en contiennent. Le rejet des dechets industriels et des produits de consommation doit ~tre reglemente afin de reduire au minimum Ia contamination de I' environnement par ce compose qui persiste et s'accumule et parses produits de decomposition.

• On ne doit proceder ~ )'incineration qu'au moyen d'incinerateurs convenables fonctionnant toujours dans des conditions optimales. Le brulage des dechets par tout autre moyen risque d'entrainer Ia formation de produits de decomposition toxiques.

3.2 Etudes a effectuer

• II faut poursuivre Ia surveillance des concentrations dans I' environnement. • II conviendrait de valider les methodes de dosage du PeBDE dans diverses matrices.

305 EHC 162: Brominated diphenylethers

• Du fait que Ia base de donn~es toxicologiques actuelle est insuffisante pour permettre d'~valuer des risques pour l'homme et l'environnement du PeBDE du commerce et en justifier !'utilisation, il conviendrait d' entreprendre les ~tudes suivantes:

~tudes compl~mentaires de canc~rog~nicit~ et ~tudes toxicologiques et ~cotoxicologiques: poursuite des travaux sur Ia formation de PBDF dans les conditions r~elles d'incendie;

~tude de m~thodes pour le recyclage des polymeres contenant du PeBDE et de leurs consequences;

~tudes sur les possibilites de migration a partir de produits contenant des retardateurs de flamme.

TETRABROMODIPHENYLETHER

Le t~trabromodiphenyl~ther n'est ni produit ni utilis~.

II n'existe aucune donn~e sur les points suivants: • Effets sur les mammiferes de laboratoire et les systemes d'~preuve in vitro • Effets sur l'homme • Effets sur les autres etres vivants au laboratoire et dans leur milieu nature! • Evaluations anterieures par des organismes internationaux.

1 Resume et evaluation

1. 1 ldentite, proprietes physiques et chimiques

Le t~trabromodiphenyl~ther du commerce est constitu~ d'un m~lange de 41% de t~tra-, 45% de penta-, et 7% d'hexabromo­ diphenyl~thers plus environ 7% d'un PBDE de structure inconnue.

306 RfJsumfJ et evaluation, conclusions et recommandations

D'apres Ia structure chimique, le t~trabromodiphenyl&her a theoriquement 42 isomeres. On ne dispose pratiquement d'aucune donn~e sur les propri~t~s physiques et chimiques de ce compos~. ~ part le logarithme du coefficient de partage n-octanol/eau, qui est 5,87-6,16.

7. 2 Production et usages

D'apres un rapport, Ia production (et !'usage) du TeBDE aurait ~t~ d'environ 1000 tonnes en 1987 au Japon. Autant qu'on sache, il n'existe actuellement aucune production sous le nom de t~tra­ bromodiph~nyl~ther, mais le compos~ est pr~sent dans Ia proportion de 24 ~ 38% dans le pentabromodiphenyl~ther du commerce.

1.3 Transport, distribution et transformation dans l'environnement

On a trouv~ des constituants du TeBDE du commerce dans des biotes, des s~iments et des boues d'~gouts. II est probable que les constituants du TeBDE du commerce (qui contiennent des quantit~s ~ peu pres ~quivalentes de PeBDE) aient un caractere r~manent et subissent une bioaccumulation.

L'~tude de Ia pyrolyse du TeBDE du commerce montre qu'~ 800 °C, il se forme des PBDF et des PBDD, mais uniquement les homologues inf~rieurs.

1.4 Concentrations dans l'environnement et exposition humaine

Au Japon, on a trouv~ du TeBDE dans les s~iments de cours d'eau a des concentrations de 12-31 JLglkg de poids sec et en Suede, a des concentrations allant jusqu'a 840 JLglkg (perte au feu). La pr~sence de TeBDE a ~t~ ~galement constat~e en Suede dans des boues d'~gouts a Ia concentration de 15 J.Lr'kg.

Au Japon, on a constat~, dans des moules et des poissons de diff~rentes provenances, Ia pr~sence de TeBDE a des concentrations allant de< 0,1 ~ 14,6 JLg de 2,2',4,4'-TeBDE/kg de poids humide. En Suede, on a captur~ dans des cours d'eau diverses especes de poissons que !'on a analys~s a Ia recherche de 2,2' ,4,4' -TeBDE. Les concentrations moyennes allaient de 0 ( < 0,1 mg/kg) ~ 100 mg/kg de graisse. L'analyse a montr~ qu'il existait au moins une source de pollution locale dans un certain cours d'eau. Des cor~gones, des

307 EHC 762: Brominated diphenyl ethers

ombles arctiques et des harengs peches en differents lieux de SuMe entre 1986 et 1987 se sont reveles contenir des concentrations de TeBDE respectivement egales a 15, 400 et 59-450 JLg de 2,2' ,4,4'­ TeBDE/kg de graisse. En Allemagne, des poissons provenant de differents cours d'eau en contenaientjusqu'a 1 mg/kg de graisse. Dans les harengs et les foies de morues peches dans Ia partie meridionale, centrale et septentrionale de Ia mer du Nord, au cours de Ia periode 1983-89, on a note une tendance a Ia diminution des concentrations de TeBDE de Ia region meridionale a Ia region septentrionale. Dans les harengs, Ia concentration allait de 8,4 a 100 JLg de 2,2' ,4,4'-TeBDE/kg de graisse. Dans le tissu musculaire d'oiseaux nichant et hivernant en mer Baltique, en mer du Nord et au Spitzberg, on a releve des con­ centrations de 2,2' ,4,4' -TeBDE de 80-370 JLg/kg de graisse. Chez des balbuzards captures en SuMe au cours de Ia periode 1982-86, on a mesure des concentrations moyennes de 1800 JLg/kg de graisse. En SuMe, on constate une tendance a !'augmentation des concentrations de 2,2' ,4,4'-TeBDE dans les sediments de Ia Baltique, les poissons d'eau douce et les oeufs d'oiseaux de mer. Dans Ia graisse de phoques de Ia mer Baltique et du Spitzberg on a observe des concentrations de 10-730 JLg/kg de graisse. Chromatographiquement, le PBDE est analogue au Bromkal 70-5. Sur des echantillons groupes de graisse de phoques de I' espece Phoca hispida et de phoques gris, preleves en SuMe au cours de Ia periode 1979-85, on a mesure des concentrations respectivement egales a 47 JLg et 650 JLg de 2,2' ,4,4' -TeBDE/kg. Dans des echantillons groupes de muscles de mammiferes terres­ tres, par exemple des lapins, des elans et des rennes, obtenus en 1985-86 en SuMe, on a observe des concentrations moyennes respec­ tivement egales a < 2, 0,82, et 0,18 JLg de 2,2',4,4'-TeBDE/kg de graisse. En Allemagne, on a trouve dans quatre echantillons de lait de vache, des concentrations de 2,5-4,5 JLg de PBDE/kg de matiere grasse, sous Ia forme de Bromkal ?ODE. Dans le meme pays et sous cette meme forme, on a retrouve du PBDE dans le lait de 25 femmes a des concentrations de 6,2-11, 1 JLg/kg de matiere grasse.

308 Resume et evaluation, conclusions et recommandations

Une estimation approximative de l'exposition de Ia population suedoise, calculee en fonction de Ia consommation de poisson en Suede, donne une absorption individuelle de 0,3 p,g de TeBDE/jour.

7.5 Effets sur les mammifiJres delaboratoire et les systiJmes d'tlpreuve in vitro

II n'existe pas de donnees sur Ie TeBDE lui-meme, cependant on dispose de donnees de toxicite aigue et de toxicite a court terme pour le PeBDE du commerce qui contient 41% de TeBDE.

1.6 Cintltique et mtltabolisme chez les animaux de laboratoire et l'homme

On ne possede qu'un minimum de donnees.

7. 7 Effets sur l'homm6

II n'existe aucune donnee.

1.8 Effets sur les autres vivants au laboratoire et dans leur milieu nature/

II n'existe aucune donnee.

2 Conclusions

2. 7 TeBDE

Les constituants du TeBDE du commerce (melange a 41% de 2,2',4,4'-tetra-; 45% de 2,2',4,4',5'-penta; 7% d'hexa-, et 7-8% de polybromodiphenylether de structure inconnue) persistent dans l'environnement et s'accumulent chez les etres vivants dans leur milieu naturel. Constituant du pentabromodiphenylether, le TeBDE est tres souvent incorpore a des polymeres comme retardateur de flamme. La population generate peut entrer en contact avec cette substance par l'intermediaire de produits fabriques apartir de ces polymeres. II est improbable qu'il puisse y avoir exposition par suite de I'extraction du compose de ces polymeres. II peut y avoir exposition humaine au

309 EHC 162: Brominated diphenyl ethers

TeBDE par l'intermediaire de Ia chaine alimentaire car on a decele Ia presence de ce compose chez des animaux dans leur milieu nature!, animaux qui servent de nourriture ll. I 'homme comme les poissons, les fruits de mer, etc. En SuMe, on observe depuis les deux dernieres decennies une augmentation des concentrations de ce compose chez les poissons et les oiseaux. On manque d'information au sujet des etudes toxicologiques ll. court et ll. long terme, des etudes de cancerogenicite ou sur Ia reproduction qui auraient pu etre faites. En outre, on ne dispose pas de donnees sur Ia cinetique et le metabolisme du produit chez les animaux de laboratoire et l'homme. II n'est pas possible d'evaluer le risque pour Ia population generale sur Ia base des donnees disponibles. On ne dispose pas non plus de donnees suffisantes pour determiner les niveaux d'exposition professionnelle ni pour se prononcer sur les effets du TeBDE. II n'existe aucune donnee sur Ia toxicite de TeBDE du commerce pour les etres vivants dans leur milieu naturel.

2. 2 Produits de dkomposition

Lorsqu'on chauffe du TeBDE ll. 800°C, il se forme des PBDF et des PBDD. II faudra etudier les dangers que cela peut comporter. II n'est guere probable que Ia population generale soit exposee de fa~on importante aux PBDF qui se forment lorsque !'on chauffe des polymeres contenant du TeBDE comme retardateur de flamme. Si !'incineration est effectuee correctement, elle n'entraine pas !'emission de bromodicxines ni de bromofuranes en quantites importantes. Le bn1lage inconsidere de produits contenant du TeBDE peut conduire ll. Ia formation de PBDF ou de PBDD en quantites indeterminees. Dans un futur Critere d'hygiene de l'environnement consacre aux PBDF et aux PBDD, !'importance de ce probleme pour l'homme et l'environnement sera examinee.

310 Resume et evaluation, conclusions et recommandations

3 Recommandations

3. 1 Recommandations generales

Du fait de sa remanence dans I' environnement et de son accumulation chez les etres vivants, il est recommancte de ne pas utiliser le TeBDE. Cependant si son usage se poursuit, il faudra prendre les precautions suivantes: • Les travailleurs qui sont employes aIa production de TeBDE et de produits qui en contiennent, doivent etre proteges contre toute exposition grace a des mesures appropriees d'hygi~me industrielle, par Ia surveillance de l'exposition professionnelle et par des mesures techniques adequates. • II convient de minimiser !'exposition environnementale par un traitement approprie des effluents et des emissions provenant des industries qui utilisent ce compose ou des produits qui en contiennent. Le rejet des dechets industriels et des produits de consommation do it etre reglemente afin de rectuire au minimum Ia contamination de I' environnement par ce compose persistant et cumulatif et ses produits de decomposition. • On ne do it procecter a I' incineration de produits contenant un retardateur de flamme a base TeBDE qu'au moyen d'incinerateurs convenables fonctionnant toujours dans des conditions optimales. Le brulage des dechets par tout autre moyen risque d'entralner Ia formation de produits de decomposition principalement formes de furanes.

3. 2 Etudes a effectuer

• II importe d'assurer une surveillance permanente des concentrations dans l'environnement. • II faudrait valider les methodes d'analyse du TeBDE dans diverses matrices. • Comme Ia base de donnees toxicologiques actuelle est insuffisante pour permettre d'evaluer le danger que le TeBDE represente pour l'homme et I'environnement, il

311 EHC 162: Brominated diphenyl ethers

faudra, si on continue a utiliser ce produit, effectuer les travaux suivants: etudes toxicologiques et ecotoxicologiques supplementaires et etudes de cancerogenicite; poursuite des etudes sur Ia formation de PBDF dans les conditions reelles d'incendie;

etude des methodes de recyclage des polym~res contenant du TeBDE et de ses consequences; recherches sur Ia possibilite de migration a partir de produits contenant des retardateurs de flamme.

TRIBROMODIPHENYLETHER

Le tribromodiphenylether n'est ni produit ni utilise. On ne dispose d'aucune donnee sur les points suivants: • Transport, distribution et transformation dans 1'environnement • Cinetique et metabolisme chez les animaux de laboratoire et l'homme

• Effets sur les mammiferes de laboratoire et les syst~mes d, epreuve in vitro • Effets sur 1'homme • Effets sur les autres etres vivants au laboratoire et dans leur milieu nature! • Evaluations anterieures par des organismes internationaux.

1 Resume et evaluation

II n'existe pas de base de donnees sur laquelle fonder une evaluation.

312 RfJsume et evaluation, conclusions et recommandations

2 Recommandations

Il convient de reduire au minimum Ia contamination des produits du commerce par du tribromodiphenyl~ther afin d'~viter ia pollution de I' environnement et I' exposition humaine.

Il faut ~viter d 'utiliser des produits commerciaux susceptibles d'entrainer Ia pollution du milieu.

DIBROMODIPHENYLETHER

Le dibromodipMnyl~ther n'est ni produit ni utilis~.

On ne dispose d'aucune donn~e sur les points suivants:

• Cin~tique et m~tabolisme chez les animaux de laboratoire et l'homme • Effets sur I 'homme • Effets sur les autres etres vivants au laboratoire et dans leur milieu naturel

• Evaluations ant~rieures par des organismes internationaux.

1 Resume et evaluation

Il n'existe pas de base de donn~es sur laquelle fonder une ~valuation.

2 Recommandations

Il convient de reduire au minimum Ia contamination des produits du commerce par du dibromodiphenylether afin d'eviter Ia pollution de l'cnvironnement et !'exposition humaine. II faut eviter d'utiliser des produits commerciaux susceptibles d'entrainer Ia pollution du milieu.

313 EHC 162: Brominated diphenyl ethers

MONOBROMODIPHENYLETHER

II n'existe aucune donnee sur les points suivants: • Cinetique et metabolisme chez les animaux de laboratoire et l'homme • Effets sur I 'homme • Evaluations anterieures par des organismes internationaux.

1 Resume et evaluation

1.1 Proprietes physiques et chimiques

II y a trois isomeres possible du monobromodiphenylether. Le p-bromodiphenylether se presente a la temperature ambiante sous Ia forme d'un liquide dont le point d'ebullition est de 305-310 °C. Le calcul montre que sa solubilite dans l'eau est de 48 mg/1 itre. Le logarithme de son coefficient de partage n-octanol!eau se situe entre 4 et 5. Sa tension de vapeur est de 0,0015 mmHg a 20 oc.

1. 2 Production et usages

Le MBDE n'est pas utilise comme retardateur de flamme. Un rapport sur sa production est paru en 1977, mais on ne lui connait pas d'usage.

1.3 Transport, distribution et transformation dans l'environnement

Sa demi-vie d'evaporation a partir de l'eau est de l'ordre de plusieurs centaines de jours. Place dans une culture de 7 jours ensemence avec des microorganismes presents dans des eaux usees domestiques, il ne subit pas de biodecomposition importante, mais il est degrade a 90% dans des boues d'egouts activees. D'apres Ia seule etude consacree a sa degradation par les bacteries terricoles, il semblerait que celles­ ci, tout au moins une souche particuliere, soient incapables d'utiliser le MBDE comme seule source de carbone.

314 Resume et evaluation, conclusions et recommandations

1.4 Concentrations dans l'environnement et exposition humaine

On a decele Ia presence de MBDE dans des echantillons d'eau superficielle preleves a proximite de sites industriels aux Etats-Unis d' Amerique; toutefois, une enqu~te analogue menee au Japon n'a pas donne de resultats. On en a egalement decele aux Etats-Unis d' Amerique dans des eaux souterraines aproximite d'une usine. Aux Etats-Unis d' Amerique, on a decele la presence de MBDE dans des sediments et des biotes aquatiques.

1. 5 Cintltique et mtltabolisme chez les animaux de /aboratoire et /'homme

II n'existe pas de donnee.

1. 6 Effets sur les mammiferes de laboratoire et les systemes d'tlpreuve in vitro

Le MBDE n'est pas teratogene, mais on ne possede aucune donnee sur la toxicite aigue ni Ia toxicite a court et a long terme de ce compose; aussi est-il impossible de proceder a une evaluation.

1. 7 Effets sur /'homme

II n'existe aucune donnee.

1.8 Effets sur les autres IJtres vivants au laboratoire et dans leur milieu nature/

Chez un poisson, Lepomis macrochirus, Ia CL50 a 96 heures serait de 4,9 mg/litre, avec une concentration sans effets observables

de moins de 2,8 mg/litre. La CL50 a 48 heures pour Ia puce d'eau est de 0,36 mg/litre avec une concentration sans effets observables de moins de 0.046 mgllitre.

2 Conclusions et recommandations

Le monobromodiphenylether n'agit pas comme retar-dateur de flamme. II peut s'accumuler chez les ~tres vivants dans leur milieu nature! et on en a decele Ia presence dans divers secteurs de

315 EHC 162: Brominated diphenylethers

I' environnement. II semblerait qu'il puisse subir une biodecomposition. Ces donnees sont trop limitees pour qu'on puisse parvenir a des conclusions quant aux niveaux d'exposi-tion et aux effets que ce compose peut avoir sur Ia population generale et les ~tres vivants dans leur milieu naturel. II n'existe aucune base de donnees toxicologiques qui plaide en faveur de l'utilisation de ce produit. II faut eviter toute utilisation susceptible de conduire a une pollution de I' environnement.

316 RESUMEN, EVALUACI6N, CONCLUSIONES Y RECOMENDACIONES

ETER DE DECABROMODIFENILO

1 Resumen y evaluaci6n

1.1 ldentidad y propiedades ffsicas y qufmicas

El eter de decabromodifenilo (DeBDE) comercial suele tener una pureza del 97-98%, con un 0,3-3,0% de eteres de difenilo nona- y octabromados. La impureza mas importante es el eter de nonabromodifenilo (NBDE). A diferencia de los otros eteres de difenilo polibromados, el DeBDE tiene un solo is6mero. El punto de fusi6n es de unos 300 oc y Ia descomposici6n se produce por encima de los 400 °C. La solubilidad en agua es de 20-30 ~tgllitro y el logaritmo del coeficiente de reparto n-octanoll agua es superior a 5. La presi6n de vapor es < 10·6 mm de Hg a 20 °C.

1. 2 Produccion y aplicaciones

Entre los eteres de difenilo bromados (del mono- al deca-), el eter de decabromodifenilo es el mas importante de fabricaci6n comercial en cuanto a producci6n y aplicaciones. A partir del decenio de 1970 se ha elaborado DeBDE comercial cada vez mas puro. Su producci6n mundial es de unas 300 000 toneladas al aiio. Se utiliza como aditivo pirorretardante en numerosos plasticos, sobre todo en el poliestireno de gran resistencia al impacto, en el tratamiento de tejidos utilizados en pasamanerfa, telas de autom6viles y tiendas de campaiia.

317 EHC 162: Brominated dipheny/ ethers

1.3 Transporte, distribucion y transformacion en el media ambiente

La fotodegradaci6n del DeBDE tiene Iugar en disolventes organi­ cos con radiaci6n ultravioleta (RUV) o Ia luz del sol y produce ~teres de difenilo con un numero menor de atomos de bromo y dibenzo­ furanos bromados. Tambi~n se produce fotodegradaci6n, en menor grado, en el agua bajo Ia acci6n de Ia luz del sol; sin embargo, no se ha detectado Ia presencia de ~teres de difenilo menos bromados ni tampoco de dibenzofuranos bromados. En funci6n del tipo de polfmero y del disolvente de extracci6n se obtiene una concentraci6n de DeBDE que esta casi en ellfmite de detecci6n o es inferior a ~1. Debido a que Ia solubilidad en agua y Ia presi6n de vapor son extremadamente bajas, es probable que el transporte del DeBDE se produzca sabre todo mediante adsorci6n sabre partfculas. Es persistente y se acumula facilmente en el sedimento y en el suelo. No se dispone de datos acerca de su biodisponibilidad a partir del sedimento y del suelo. En un estudio realizado en Ia trucha irisada no se detect6 bioacumulaci6n en Ia carne, Ia piel o las vfsceras durante mas de 48 horas. No es probable Ia bioacumulaci6n del DeBDE, debido a su peso molecular relativamente alto. A Ia larga, los productos que contienen DeBDE comercial se eliminan en vertederos o mediante incineraci6n. El DeBDE, en ultimo t~rmino, se puede lixiviar de los vertederos. Se pueden producir dibenzofuranos polibromados (PBDF) y mezclas de dibenzo­ furanos y dibenzodioxinas halogenados en incendios de los vertederos o por una incineraci6n incompleta. Los productos que contienen DeBDE comercial pueden contribuir a estas emisiones. La pir6lisis del propio DeBDE comercial y de los polfmeros (HIPS, PBT, polipropileno industrial) con DeBDE en presencia de oxfgeno produjo PBDF, detectandose en menor grado dibenzo­ dioxinas polibromadas (PBDD). La formaci6n maxima de PBDF tiene Iugar a 400-500 °C, pero se puede producir a temperaturas de

hasta 800 oc; el Sb20 3 ejerce una funci6n catalftica en Ia formaci6n de PBDF y PBDD. La formaci6n de PBDF y PBDD y las cantidades encontradas dependen de Ia temperatura, el contenido de oxfgeno y Ia duraci6n

318 Resumen y evaluacion, conclusiones y recomendaciones

de Ia pir6lisis. En ausencia de oxfgeno, se forman sobre todo polibromobencenos y polibromonaftalenos.

1.4 Niveles medioambientales y exposici6n humilna

En Ia vecindad de las instalaciones de fabricaci6n se han 3 identificado concentraciones de DeBDE de hasta 25 11g/m . No se detect6 en las muestras de agua recogidas en el Jap6n durante el perfodo de 1977-91. Sin embargo, se observ6 en el sedimento de rfos recogido en el J ap6n durante el mismo perfodo a concentraciones de hasta unos 12 mg/kg de peso seco. En los Estados Unidos se encontr6 DeBDE (hasta 1 g/kg) en el sedimento de los rfos cercanos a una fabrica. No se detect6 su presencia en las muestras de peces recogidas en el Jap6n, aunque en una muestra de mejillones se observ6 una concentraci6n ligeramente superior a1 nivel de detecci6n. Aunque no se encontr6 en las muestras de tejido adiposo humano recogidas en el Jap6n, en los Estados Unidos se observ6 en 3 de 5 muestras de este tipo de tejido. La exposici6n humana al DeBDE se puede producir en el curso de Ia fabricaci6n y Ia formulaci6n en polfmeros. La exposici6n de Ia poblaci6n general al DeBDE es insignificante. En Ia determinaci6n de Ia exposici6n en el trabajo a los productos de degradaci6n del DeBDE durante Ia fabricaci6n, formulaci6n o utilizaci6n se puso de manifiesto que las muestras de aire pr6ximas a1 cabezal del extrusor contenfan concentraciones elevadas de PBDF. En el aire de Ia sal a de trabajo se encontraron niveles mas bajos. Se detect6 asimismo en muestras del material de limpieza. Se ha demostrado que Ia aplicaci6n de buenas tecnicas industriales reduce Ia exposici6n ocupacional al PBDF. No es probable una exposici6n significativa de Ia poblaci6n general a las impurezas de PBDF de los polfmeros con caracterfsticas pirorretardantes.

1.5 Cinetica y metabolismo en animales de laboratorio y en el ser humano

El DeBDE tiene una escasa absorci6n desde el tracto gastrointestinal y se excreta con rapidez tras su inyecci6n.

319 EHC 162: Brominated diphenyl ethers

Los resultados de los estudios metab6licos en ratas utilizando DeBDF marcado con 14C indicaron una semivida para su desaparici6n del organismo de menos de 24 horas, siendo Ia ruta principal de eliminaci6n tras Ia ingesti6n oral Ia vfa fecal. En Ia orina o el aire expirado no se encontr6 una actividad apreciable de 14C (inferior a! 1 %). Las ratas alimentadas con 0, 1 mg/kg de peso corporal a! dfa, durante un perfodo de basta dos aiios, no mostraron acumulaci6n de DeBDF en el suero, los riiiones, los musculos o los testfculos, como se comprob6 mediante una determinaci6n del bromo total. La acumulaci6n de bromo en el hfgado alcanz6 un nivel estacionario a los 30 dfas y desapareci6 en un perfodo de 10 dfas despues del tratamiento. Tras 180 dfas de tratamiento, el nivel de bromo en el hfgado de las ratas tratadas no era superior a! de las testigci. En el tejido adiposo se acumul6 una concentraci6n baja de bromo total, que se mantenfa tras 90 dfas con una alimentaci6n sin DeBDE; se desconoce Ia naturaleza del bromo acumulado. Habida cuenta de que el DeBDE representaba s6lo el 77% de Ia mezcla comercial utilizada, el "bromo" podrfa proceder del NBDE o el OBDE.

1. 6 Efectos en los animales de laboratorio yen sistemas de prueba in vitro

La toxicidad aguda del DeBDE en los animales de laboratorio es baja. La sustancia no es irritante para Ia pie! o los ojos de los conejos. No es cloracnegenico en Ia pie! de los conejos, ni tampoco sensibilizador cutaneo humano. Se realizaron pruebas de toxicidad aguda y de comedogenicidad de los productos de Ia combusti6n del poliestireno pirorretardante con

DeBDE y Sb 20 3 • La DL50 por vfa oral del hollfn y Ia carbonilla fue > 2000 mg/kg de peso corporal. No se observ6 inducci6n de efectos adversos en los estudios de toxicidad a corto plazo realizados en ratas y ratones con niveles de DeBDE (pureza > 97%) de 100 g/kg (4 semanas) 6 50 g/kg de alimentos (13 semanas, equivalente a 2500 mg/kg de peso corporal de Ia rata). En un estudio de reproducci6n de una sola generaci6n en ratas no se observaron efectos adversos con niveles de dosis de 100 mg/kg de peso corporal. El DeBDE no produjo efectos teratogenicos en los fetos de las ratas que recibieron dosis de

320 Resumen y evaluacion, conclusiones y recomendaciones

100 mg/kg de peso corporal. Con 1000 mg/kg de peso corporal se detectaron malformaciones como el retraso de Ia osificaci6n. En varias pruebas realizadas no se ha observado que tenga efectos mutagenicos. En un estudio de carcinogenicidad en ratas y ratones, se administraron concentraciones de DeBDE (pureza 94-99%) de basta 50 g/kg de alimentos. Se observ6 un aumento en el m1mero de adenomas hepaticos (pero no de carcinomas) de las ratas macho que recibieron 25 g/kg y en las ratas hembra con 50 g/kg. En ratones macho tratados con 25 g/kg se detect6 una frecuencia mayor de adenomas y carcinomas hepatocelulares (combinados) y con ambos niveles de dosis un aumento de adenomas/carcinomas (combinados) de las celulas foliculares del tiroides. En los ratones hembra no se apreci6 ningl1n incremento de Ia frecuencia de tumores. Se obtuvo una prueba equfvoca de carcinogenicidad en ratas macho y hembra y en ratones macho s61o con dosis de 25-50 g de DeBDE/kg de alimentos. Dado que los resultados de todas las pruebas de mutagenicidad han sido negativos, se puede concluir que el DeBDE carece de carcinogenicidad genot6xica. IARC (1990) concluy6 que las pruebas de carcinogenicidad del DeBDE en los animates de experimentaci6n eran limitadas. Los niveles de dosificaci6n muy elevados, Ia falta de genotoxicidad y las pruebas mfnimas de carcinogenicidad ponen de manifiesto que el DeBDE, a las concentraciones de exposici6n actuates, no representa un riesgo de carcinogenesis para el ser humano.

1. 7 Efectos en el ser humano

No se detectaron signos de sensibilizaci6n cutanea en una prueba realizada con 200 personas expuestas al DeBDE. En un estudio de morbilidad realizado con el personal del extrusor que mezcla polibutilenterftalato que contiene DeBDE, con Ia consiguiente exposici6n potencial al PBDD y al PBDF durante 13 afios, no se observaron efectos nocivos, aun cuando se detectaron en sangre 2,3,7,8-TeBDF y -TeBDD. Los resultados de los estudios inmunol6gicos pusieron de manifiesto que el sistema inmunitario de las personas expuestas no se habfa visto negativamente afectado despues de 13 afios.

321 EHC 762: Brominated diphenyl ethers

1.8 Efectos en otros organismos en el /aboratorio y en el medio ambiente

Las CEsoS para el crecimiento de tres algas unicelulares marinas fueron superiores a 1 mg de DeBDE/Iitro. No se dispone de mas informaci6n sobre los efectos del DeBDE en otros organismos en el laboratorio y en el medio ambiente.

2 Conclusiones

2. 7 DeBOE

El DeBDE se utiliza ampliamente en polfmeros como aditivo pirorretardante. El contacto de Ia poblaci6n general se produce a traves de productos fabricados con dichos polfmeros. La exposici6n es muy escasa, puesto que no es facil extraer el DeBDE de los polfmeros. La toxicidad aguda es muy baja y Ia absorci6n del tracto gastrointestinal mfnima. Asf pues, el riesgo para Ia poblaci6n general se puede considerar insignificante. La exposici6n en el trabajo se da con el DeBDE en forma de partfculas. El control del polvo durante Ia fabricaci6n y el empleo reducin1 el riesgo para los trabajadores de manera suficiente. El DeBDE es persistente y se une a partfculas del medio ambiente; es facil que se acumule en el sedimento, pero no es probable su bioacumulaci6n. Aunque las pruebas disponibles indican que Ia fotodegradaci6n ambiental en agua no producen eteres de difenilo o dibenzofuranos con menor mlmero de atomos de bromo, apenas se conoce nada sobre Ia degradaci6n en otros medios. La informaci6n sobre Ia toxicidad del DeBDE para los organismos del medio ambiente es mfnima.

2. 2 Productos de degradacion

Se puede producir PBDF y, en cierta medida, PBDD cuando se somete el DeBDE, o los productos que lo contienen, a temperaturas de 300-800 °C. Hay que estudiar los posibles peligros asociados a estos productos. La incineraci6n controlada de manera adecuada no produce una emisi6n de cantidades significativas de dioxinas o furanos bromados.

322 Resumen y evaluacion, conclusiones y recomendaciones

Cualquier combusti6n no controlada de productos con DeBDE puede dar Iugar a una formaci6n no cuantificada de PBDF/PBDD. De su importancia para el ser humano y el media ambiente se ocupara un futuro m.imero de Criterios de Salud Ambiental. Se ha detectado PBDR en Ia sangre de las personas que trabajan en Ia producci6n de plasticos con DeBDE. No se han observado efectos adversos relacionados con esta exposici6n. Con un buen control tecnico se puede evitar Ia exposici6n de los trabajadores al PBDF.

3 Recomendaciones

3. 1 Generales

• Las personas que trabajan en Ia fabricaci6n de DeBDE y productos que lo contienen deben estar protegidas de Ia exposici6n mediante Ia aplicaci6n de medidas adecuadas de higiene industrial, Ia vigilancia de Ia exposici6n en el trabajo y controles tecnicos. • Hay que reducir al mfnimo Ia exposici6n ambiental mediante el tratamiento adecuado de efluentes y emisiones industriales que contienen el compuesto o sus productos. Se debe controlar Ia eliminaci6n de los residuos industriales y los productos de consumo para que sea mfnima Ia contaminaci6n del media ambiente con esta sustancia persistente y sus productos de degradaci6n. • Los fabricantes deben reducir al mfnimo los niveles de impurezas en los productos comerciales de DeBDE, utili­ zando las mejores tecnicas disponibles. Se recomienda una pureza del 97% o superior. • La incineraci6n s6lo se debe realizar en incineradores adecuados que funcionen siempre en condiciones 6ptimas. La quema par otros medias puede dar Iugar a Ia formaci6n de PBDF y PBDD.

323 EHC 162: Brominated diphenyl ethers

3. 2 Otros estudios

• Se deberan realizar en los organismos pertinentes nuevos estudios sobre Ia biodisponibilidad y Ia toxicidad del DeBDE unido al sedimento. • Hay que mantener una vigilancia constante de los niveles en el medio ambiente. • Se debe investigar con mas detalle Ia formaci6n de PBDF en incendios reales. • Hay que estudiar mas a fondo Ia biodegradaci6n en el medio ambiente y Ia fotodegradaci6n en compartimentos distintos del agua. • Se debe investigar los posibles metodos y las consecuencias del reciclaje de polfmeros que contienen DeBDE. • Hay que validar metodos analfticos para el DeBDE en diversos aglomerantes.

ETER DE NONABROMODIFENILO

El eter de nonabromodifenilo no se fabrica ni se utiliza. No se dispone de datos sobre los aspectos siguientes: • Transporte, distribuci6n y transformaci6n en el medio ambiente • Niveles medioambientales y exposici6n humana • Cinetica y metabolismo en animales de laboratorio y en el ser humano • Efectos en los animales de laboratorio y en sistemas de prueba in vitro • Efectos en el ser humano • Efectos en otros organismos en el laboratorio y en el medio ambiente • Evaluaciones anteriores por parte de 6rganos internacionales.

324 Resumen y evaluacion, conclusiones y recomendaciones

1 Resumen y evaluaci6n

No hay ninguna base de datos sobre Ia cual realizar una evaluaci6n.

2 Recomendaciones

Los niveles de contaminaci6n de los pirorretardantes bromados comerciales que contienen eter de nonabromodifenilo deberfan ser mfnimos a fin de evitar Ia contaminaci6n del medio ambiente y Ia exposici6n humana.

ETER DE OCTABROMODIFENILO

El eter de octabromodifenilo puro no se fabrica ni se utiliza. No se dispone de datos sobre los aspectos siguientes: • Cinetica y metabolismo en animales de laboratorio y en el ser humano • Efectos en el ser humano • Efectos en otros organismos en el laboratorio y en el medio ambiente • Evaluaciones anteriores por parte de 6rganos internacionales.

1 Resumen y evaluaci6n

1. 1 Jdentificacion y propiedades fisicas y qufmicas

El eter de octabromodifenilo (OBDE) comercial es una mezcla formada por alrededor del 11% de PeBDE/HxBDE, 44% de HpBDE, 31-35 % de OBDE, 10% de NBDE y 0,5% de DeBDE. En funci6n de su estructura qufmica, existen 12 posibles is6meros del OBDE y 24 del HpBDE. El punto de fusi6n oscila entre unos 80 oc y > 200 °C. La presi6n de vapor es < 10·7 mm de Hg. La solubilidad en agua es

325 EHC 162: Brominated diphenylethers

baja y el logaritmo del coeficiente de reparto n-octanol/agua es > 5,5. Las variaciones anteriores obtenidas en los datos ffsicos pueden deberse a diferencias de composici6n en las mezclas probadas.

1. 2 Producci6n y aplicaciones

El consumo anual de OBDE comercial en todo el mundo es de 6000 toneladas, el 70% del cual se utiliza como pirorretardante en ABS para Ia producci6n de computadores y cabinas comerciales. El OBDE es el segundo mas utilizado de los pirorretardantes de PBDE.

1.3 Transporte, distribuci6n y transformaci6n en el media ambiente

Se han detectado componentes de OBDE comercial en el sedimento acuatico y en Ia grasa humana. En Ia biota se han encontrado algunos componentes de menor mimero de atomos de bromo (HxBDE y PeBDE) del producto comercial. No se ha observado OBDE, pero normalmente no se ha investigado Ia presencia de HpBDE y NBDE. Es facil que persistan los componentes comerciales de OBDE, pero a medida que el numero de atomos de bromo aumenta por encima del HxBDE disminuye Ia probabilidad de bioacumulaci6n. En Ia carpa se ha encontrado un factor de bioacumulaci6n inferior a 2 para un producto de OBDE comercial. En Ia pir6Iisis a 600 oc del producto comercial como tal o de

polfmeros que lo contienen como aditivo pirorretardante (con Sb20 3 o sin el) se ha puesto de manifiesto Ia producci6n de PBDF y, en grado mucho menor, PBDD. El tratamiento de ABS con

OBDE/Sb20 3 en diferentes condiciones permiti6 demostrar que, en el caso de tratamiento normal, s6lo se formaban pequeiias concentraciones de PBDF. En condiciones de uso excesivo, las concentraciones fueron mucho mas elevadas. Las concentraciones de PBDD fueron bajas en ambos casos.

1.4 Niveles medioambientales y exposici6n humana

En una serie de muestras recogidas en el Jap6n durante 1987 y 1988 no se detect6 OBDE ni los componentes de menor numero de atomos de bromo del producto comercial. Tambien se analizaron

326 Resumen y evaluacion, conclusiones y recomendaciones

muestras del sedimento y se encontr6 OBDE en alrededor del 2-6% de las muestras a concentraciones que oscilaban entre 8 y 22 p,g/kg de peso seco. En el sedimento se observ6 asimismo Ia presencia de componentes de menor mimero de

1.5 Cinetica y metabolismo en animales de laboratorio y en el ser humano

No se dispone de datos.

1. 6 Efectos en los animales de laboratorio yen los sistemas de prueba in vitro

La toxicidad aguda del producto comercial en los animates de laboratorio es baja. No es irritante cutaneo y s6lo produce una ligera irritaci6n ocular en los conejos. En los estudios de toxicidad a corto plazo (4 semanas y 13 semanas) se observ6 que en las ratas que recibieron dosis de 100 mg/kg de alimentos se produjo un mayor peso del hfgado y cambios microsc6picos caracterizados por un aumento de tamafio de las celulas parenquimaticas hepaticas de Ia zona centrolobular y media que contienen estructuras granulares. Estos cambios hepaticas fueron mas grave., con dosis mas elevadas, es decir, 1000 y 10 000 mg/kg de alimentos. A esto hay que afiadir que se observ6 hiperplasia en el tiroides. El contenido total de bromo en los tejidos aument6 durante el estudio y disminuy6 lentamente durante un perfodo de recuperaci6n. Los cambios hepaticas fueron reversibles. En un estudio de inhalaci6n con polvo de OBDE micronizado (8 horas a! dfa durante 14 dfas consecutivos) no se observaron efectos con exposiciones a 1,2 mglm\ pero a 12 mg/m3

327 EHC 162: Brominated diphenyl ethers

se produjeron en el hfgado los cambios descritos en los estudios de administraci6n oral. El OBDE comercial a dosis relativamente bajas produjo en ratas un aumento del citocromo P450 y Ia inducci6n de enzimas micros6micas hepaticas, como Ia UDP-glucuronil transferasa y Ia benzo[a]pireno hidroxilasa. El OBDE comercial indujo efectos porfirinogenicos en cultivos de celulas hepaticas de embri6n de polio. Su potencial teratogenico se prob6 en ratas; con dosis elevadas (25,0 y 50,0 mg/kg de peso corporal) se detectaron procesos de resorci6n y osificaci6n retardada de diferentes huesos, asf como malformaciones fetales. Las malformaciones observadas tras la administraci6n de dosis de 25 mg/kg de peso corporal y superiores probablemente se debieron en buena parte a Ia toxicidad materna. Estos cambios no se advirtieron a dosis de 15,0 mg/kg de peso corporal o inferiores. No se obtuvieron pruebas de actividad teratogenica en los conejos, pero se observ6 fetotoxicidad a una dosis t6xica para las madres de 15 mg/kg de peso corporal. En los estudios de teratogenicidad se puso de manifiesto Ia ausencia de efectos a una dosis de 2,5 mg/kg de peso corporal. En estudios de 28 dfas y 90 dfas realizados en ratas se observ6 que 100 mg de OBDE por kg de alimentos (equivalentes a 5 mg/kg de peso corporal) producfan efectos mfnimos en el hfgado. No se estableci6 un nivel sin efectos. Los resultados de las pruebas de mutagenicidad. incluso con un ensayo de ADN fuera de programa, los ensayos microbiol6gicos in vitro y un ensayo de intercambio de cromatidas hermanas con celulas de ovario de hamster chino fueron negativos. No se dispone de resultados de pruebas de carcinogenicidad a largo plazo.

1. 7 Efectos en el ser humano

No se dispone de datos.

1. 8 Efectos en otros organismos en el laboratorio y en e/ media ambiente

Los datos disponibles son mfnimos.

328 Resumen y evaluacion, conc/usiones y recomendaciones

2 Conclusiones

2.1 OBOE

El OBDE comercial es una mezcla de eteres de hexa-,hepta-, octa-, y nonabromodifenilo, todos ellos persistentes en el medio ambiente, fundamentalmente unidos al sedimento. El OBDE se afiade con mucha frecuencia a los polfmeros como aditivo pirorretardante. El contacto de Ia poblaci6n general tiene Iugar mediante los productos fabricados con estos polfmeros. No es probable la exposici6n por extracci6n de los polfmeros. La toxicidad aguda del OBDE es baja. No se dispone de informaci6n sobre su absorci6n y eliminaci6n en los mamfferos. No es teratogenico ni mutagenico. Nose dispone de estudios de toxicidad y carcinogenicidad a largo plazo. En el tejido adiposo humano se han identificado varios componentes del OBDE comercial. El riesgo grave para la poblaci6n general probablemente es bajo. No es posible evaluar el riesgo de exposici6n prolongada, debido a Ia falta de los estudios de toxicidad correspond ientes. La falta de informaci6n no permite sacar conclusiones sobre la exposici6n en el trabajo al OBDE o sus efectos. La informaci6n sobre la toxicidad del OBDE para los organismos en el medio ambiente es limitada. Los componentes de la mezcla de OBDE comercial con menor mimero de atomos de bromo podrfan dar Iugar a una bioacumulaci6n en los organismos.

2. 2 Productos de degradaci6n

Puede formarse PBDF, y en cierto grado PBDD, cuando el OBDE o los productos que lo contienen se calientan a 400-800 °C. Hay que investigar los posibles peligros relacionados con esta transformaci6n. No es probable que Ia exposici6n de la poblaci6n general a las impurezas de PBDF en los polfmeros pirorretardantes sea significativa. La incineraci6n adecuadamente controlada no deberfa producir Ia emisi6n de cantidades importantes de dioxinas y furanos bromados. Cualquier combusti6n no controlada de productos que

329 EHC 162: Brominated diphenyl ethers

contienen OBDE comercial puede dar Iugar a Ia producci6n de cantidades no cuantificadas de PBDF/PBDD. Su importancia para el ser humano y el medio ambiente sera objeto de estudio en un futuro EHC sobre el PBDF/PBDD.

3 Recomendaciones

3. 1 Generales

• En Ia fabricaci6n de OBDE comercial se deben utilizar las mejores tecnicas disponibles, a fin de reducir al mfnimo los niveles de hexabromodifenilo y los compuestos analogos de menor mimero de atomos de bromo, debido a su posible bioacumulaci6n en el medio ambiente. • Los trabajadores que intervienen en Ia fabricaci6n de OBDE y de los productos que contienen el compuesto deben estar protegidos de Ia exposici6n mediante Ia aplicaci6n de medidas de higiene industrial adecuadas, Ia vigilancia de Ia exposici6n en el trabajo y controles tecnicos. • Se debe reducir al mfnimo Ia exposici6n ambiental mediante el tratamiento adecuado de los efluentes y las emisiones en las industrias que utilizan el compuesto o sus productos. Hay que controlar Ia eliminaci6n de desechos industriales y de los productos de consumo, a fin de reducir al mfnimo Ia contaminaci6n del medio ambiente con este material persistente y los productos de su degradaci6n. • La incineraci6n de materiales con aditivos pirorretardantes a base de OBDE se debe realizar s6lo en incineradores adecuados que funcionen siempre en condiciones 6ptimas. La combusti6n par cualquier otro medio puede dar Iugar a Ia producci6n de PBDF y PBDD.

3. 2 Otros estudios

Habida cuenta de que Ia base de datos toxico16gica actual no es adecuada para evaluar los peligros del OBDE comercial para el ser humano y el medio ambiente y a fin de mejorar su uso se deberfan realizar los siguientes estudios:

330 Resumen y evaluacion, conclusiones y recomendaciones

• Investigaciones sobre Ia biodisponibilidad y Ia ecotoxicidad de los componentes del OBDE comercial unidos al sedimento utilizando los organismos pertinentes. • Mayor vigilancia de los niveles en el medio ambiente de los componentes de OBDE comercial. • Estudios de toxicidad y carcinogenicidad a largo plazo del OBDE comercial. • Vigilancia de Ia exposici6n en el trabajo al OBDE comercial. • Otras investigaciones sobre Ia formaci6n de PBDF en incendios reales. • Nuevos estudios sobre biodegradaci6n y fotodegradaci6n en el medio ambiente en compartimentos diferentes del acu;itico. • Investigaci6n de posibles metodos y consecuencias del reciclaje de polfmeros que contienen OBDE. • Validaci6n de metodos analfticos para el OBDE en varios aglomerantes. • Investigaciones sobre Ia posibilidad de migraci6n a partir de diferentes tipos de polfmeros.

ETER DE HEPTABROMODIFENILO

El eter de heptabromodifenilo no se fabrica ni se utiliza. No existe una base de datos sobre Ia que hacer una evaluaci6n del HpBDE. No se dispone de datos sobre los aspectos siguientes: • Cinetica y metabolismo en animales de laboratorio y en el ser humano • Efectos en el ser humano • Efectos en otros organismos en el laboratorio y en el medio ambiente • Evaluaciones previas por parte de 6rganos internacionales.

331 EHC 162: Brominated dipheny/ ethers

Dado que el HpBDE es el principal componente del eter de octabromodifenilo comercial, el resumen, evaluaci6n, conclusiones y recomendaciones del OBDE comercial son aplicables a! HpBDE "comercial" .

ETER DE HEXABROMODIFENILO

Aunque el eter de hexabromodifenilo no se fabrica ni se utiliza, es posible encontrarlo como contaminante de los eteres bromados del difenilo comerciales. Se debe reducir al mfnimo tales niveles del eter de hexabromodifenilo para evitar la contaminaci6n del . media ambiente y Ia exposici6n humana. No existe una base de datos sabre la que hacer una evaluaci6n. No se dispone de datos sabre los aspectos siguientes: • Efectos en mamfferos de laboratorio y en sistemas de ensayo in vitro • Efectos en el ser humano • Efectos en otros organismos en el laboratorio y en el media ambiente • Evaluaciones previas por parte de 6rganos internacionales.

ETER DE PENTABROMODIFENILO

El eter de pentabromodifenilo no se fabrica ni se utiliza. No se dispone de datos sabre los aspectos siguientes: • Efectos en el ser humano

• Efectos en otros organismos en el laboratorio y en el medio ambiente

332 Resumen y evaluacion, conclusiones y recomendaciones

• Evaluaciones previas por parte de 6rganos internacionales.

1 Resumen y evaluaci6n

1. 1 ldentificacion y propiedades ffsicas y qufmicas

El eter de pentabromodifenilo comercial (PeBDE) es una mezcla de eteres de tetra-, penta-, y hexabromodifenilo. Contiene aproximadamente un 50-60% de PeBDE y un 24-38% de TeBDE. Habida cuenta de su estructura qufmica, hay seis posibles is6meros del PeBDE y 42 del TeBDE. Los productos comerciales parecen estar formados por tres componentes principales, a saber, 2,2',4,4',5'-PeBDE, 2,2',4,4'-TeBDE y un compuesto amHogo no identificado con cinco atomos de bromo. El punto de fusi6n es de -7 a -3 oc y el de ebullici6n superior a 200 oc. La presi6n de vapor es baja: < 10·7 mm de Hg; Ia solubilidad en agua es insignificante. Ellog del coeficiente de reparto n-octanol/agua es > 6.

1. 2 Produccion y aplicaciones

El PeBDE se utiliza como aditivo de resinas epoxi, resinas fen61icas, poliesteres y poliuretano, asf como de materiales textiles. El consumo mundial es de unas 4000 toneladas anuales. Es uno de los principales eteres bromados del difenilo pirorretardantes comerciales.

1.3 Transporte, distribucion y transformacion en el media ambiente

Se han detectado componentes del PeBDE comercial en muestras de biota, sedimento y fangos cloacales. Es facil que sean persistentes y tengan capacidad de bioacumulaci6n. En las carpas se ha encontrado un factor de bioacumulaci6n para el PeBDE superior a 10 000. En los estudios de pir6lisis con PeBDE comercial se observ6 Ia form

333 EHC 162: Brominated diphenyl ethers

1.4 Niveles medioambientales y exposici6n humana

En muestras obtenidas de rfos y estuarios del J ap6n se detectaron niveles que variaban entre la ausencia de PeBDE ( < 2 JLglkg) y 28 JLglkg de peso seco. En Suecia, la concentraci6n en muestras de sedimento de algunos rfos alcanz6 un valor de hasta 1200 JLg de 2,2',4,4',5'-PeBDE/kg. Tambien en el amilisis de fangos cloacales de Suecia se puso de manifiesto Ia presencia de PeBDE. En los mejillones y peces recogidos en diferentes costas del J ap6n durante el perfodo de 1981-85 se encontraron concentraciones de 0,4 y 2,8 JLg de PeBDE/kg de peso humedo de dos de cinco muestras de mejillones. No se detect6 PeBDE en los peces (lfmite de determinaci6n < 0,2 JLglkg). Se inform6 de concentraciones de 1,9- 22 JLglkg de peso fresco en muestras de hfgado de bacalao procedente del mar del Norte. En Suecia se encontraron concentraciones de 7,2 a 64 JLg de 2,2' ,4,4' ,5' -PeBDE/kg de grasa en coregonos de agua dulce y en arenques recogidos en diversos lugares. En una mezcla de grasa de focas oceladas y focas grises recolectada en Suecia entre 1979 y 1985 se encontr6 una concentraci6n media de 1, 7 JLg y 40 JLg de 2,2' ,4,4' ,5' -PeBDE/kg de grasa, respectivamente. En mezclas de muestras de musculo de conejo y rat6n y en muestras de sebo de reno recogidas en Suecia de 1985 a 1986 se determin6 una concentraci6n < 0,3 JLg, 0,64 JLg y 0,26 JLg de 2,2' ,4,4' ,5'-PeBDE/kg de grasa, respectivamente. Las muestras de musculo de quebrantahuesos recogidas en Suecia en 1982-86 contenfan una concentraci6n media de 140 JLg de 2,2',4,4',5'- PeBDE/kg de grasa. En los ultimos decenios se han multiplicado por diez los niveles de dos is6meros del PeBDE en los huevos de arao del Baltico. La concentraci6n de dichos is6meros en los lucios de un lago de la regi6n meridional de Suecia tambien ha experimentado un aumento (del cuadruple). Se ha observado asimismo un aumento considerable en los muestreos realizados en el sedimento del Baltico en distintos afios durante el ultimo decenio. Aunque se dispone de una informaci6n muy escasa sobre Ia exposici6n humana, una estimaci6n aproximada de Ia exposici6n de

334 Resumen y evaluacion, conclusiones y recomendaciones

la poblaci6n sueca a traves del consumo de pescado parece indicar una absorci6n diaria de 0, 1 p,g de PeBDE/persona.

1.5 Cinetica y metabolismo en animales de laboratorio y en el ser humano

La semivida del PeBDE s6lo se ha investigado en la grasa perirrenal de ratas. La semivida media oscil6 entre 25 y 47 dfas, en funci6n del sexo del animal y del tipo de is6mero.

1.6 Efectos en mamfferos de laboratorio yen sistemas de ensayo in vitro

La toxicidad aguda por vfa oral del PeBDE comercial en ratas es baja; la toxicidad dermica en conejos es tambien escasa. La exposici6n de ratas a inhalaci6n durante perfodos breves y Ia aplicaci6n de PeBDE al saco conjuntival de conejos produjo s61o efectos transitorios leves. En los estudios de toxicidad a corto plazo realizados en ratas (4 y 13 semanas), las concentraciones de 100 mg/kg de alimentos produjeron un aumento del peso del hfgado y Iigeras alteraciones histol6gicas. Los cambios consistieron en el agrandamiento de las celulas parenquimaticas hepaticas, que tenfan un aspecto granular y contenfan "cuerpos redondos" eosin6filos. Se produjo en el hfgado un aumento de Ia cantidad total de bromo dependiente de Ia dosis y los niveles se mantuvieron durante un perfodo largo, de hasta 24 semanas. Se observ6 una hiperplasia tiroidea ligera de caracter reversible. Tras Ia administraci6n oral de PeBDE en dosis diarias bajas, del orden de 0,78 p,moles/kg de peso corporal, se detect6 Ia inducci6n de enzimas hepaticas y un aumento de concentraci6n del citocromo P450. Los resultados de Ia pruebas de teratogenicidad y mutagenicidad fueron negativos. No se ha informado de estudios de carcinogenicidad a largo plazo.

335 EHC 162: Brominated diphenyl ethers

7. 7 Efectos en el ser humano

No se dispone de datos.

7.8 Efectos en otros organismos en el /aboratorio y en el medio ambiente

Se dispone de muy pocos datos.

2 Conclusiones

2. 7 PeBDE

El PeBDE comercial (mezcla de varios eteres: 24-38% de tetra-, 50-60% de penta- y 4-8% de hexabromodifenilo) es persistente y se acumula en los organismos y en el medio ambiente. El PeBDE comercial de utiliza ampliamente incorporado a polfmeros como aditivo pirorretardante. El contacto de Ia poblaci6n general tiene Iugar a traves de los productos fabricados con estos polfmeros. No es probable Ia exposici6n debida a su extracci6n de ellos. Se puede producir exposici6n humana a! PeBDE mediante Ia cadena alimentaria, puesto que se ha detectado su presencia en organismos del medio ambiente que son artfculos alimenticios humanos, como peces, crustaceos, etc. En los dos ultimos decenios se han determinado cantidades crecientes en los peces y las aves de Suecia. La toxicidad aguda del PeBDE comercial es baja. No se dispone de informaci6n acerca de su absorci6n y eliminaci6n en los mamfferos. Tampoco ~e han realizado estudios sobre Ia reproducci6n, Ia toxicidad a largo plazo y Ia carcinogenicidad. De los datos disponibles no se puede determinar el riesgo de Ia poblaci6n general. Se carece de Ia informaci6n necesaria para sacar conclusiones sobre los niveles de exposici6n en el trabajo o los efectos del PeBDE comercial. Se dispone de una informaci6n limitada sobre Ia toxicidad del PeBDE comercial para los organismos en el medio ambiente.

336 Resumen y evaluacion, conclusiones y recomendaciones

2. 2 Productos de degradaci6n

AI calentar el PeBDE (o los productos que lo contienen) a 400- 800 oc se producen PBDF, yen cierta medida el PBDD. Habrfa que ocuparse de los posibles peligros derivados de su formaci6n. La exposici6n de Ia poblaci6n general al PBDF de los polfmeros pirorretardantes con PeBDE probablemente carece de importancia. La incineraci6n controlada de forma adecuada no produce una emisi6n de cantidades significativas de dioxinas y furanos bromados. La combusti6n no controlada de productos con PeBDE puede dar Iugar a Ia formaci6n de cantidades no cuantificadas de PBDF/PBDD. En un futuro EHC sobre PBDF y PBDD se prestara atenci6n a su importancia para el ser humano y el medio ambiente.

3 Recomendaciones

3. 1 Generales

Dada su persistencia en el medio ambiente y Ia acumulaci6n en organismos nose deberfa utilizar PeBDE comercial. Sin embargo, si se va a seguir usando hay que tener en cuenta los puntos siguientes: • Se debe proteger de Ia exposici6n a los trabajadores que intervienen en Ia fabricaci6n de PeBDE y de los productos que contienen el compuesto mediante medidas adecuadas de higiene industrial, vigilancia de Ia exposici6n en el trabajo y controles tecnicos. • Hay que reducir al mfnimo Ia exposici6n ambiental mediante el tratamiento adecuado de etluentes y emisiones de las industrias que utilizan el compuesto o sus productos. Se debe controlar Ia eliminaci6n de desechos industriales y de productos de consumo para evitar en lo posible Ia contaminaci6n del medio ambiente con este producto persistente y acumulable, asf como con sus productos de degradaci6n. • La incineraci6n de materiales pirorretardantes con PeBDE s6lo se debe realizar en incineradores adecuados que funcionen siempre en condiciones 6ptimas. La quema por otros medios dara Iugar a Ia formaci6n de productos de descomposici6n t6xicos.

337 EHC 162: Brominated diphenyl ethers

3. 2 Otros estudios

• Se requiere una vigilancia permanente de sus niveles en el medio ambiente. • Se deben validar metodos de determinaci6n del PeBDE en diversos aglomerantes. • Habida cuenta de que Ia base de datos toxicol6gicos actual no es adecuada para evaluar los peligros del PeBDE comercial para el ser humano y el medio ambiente y, a fin de mejorar su uso, se deberfan realizar los siguientes estudios: estudios adicionales toxicol6gicos, carcinogenicos y ecotoxicol6gicos; nuevas investigaciones sobre Ia formaci6n de PBDF en condiciones de incendios reales; investigaci6n de posibles metodos de reciclaje de polfmeros que contienen PeBDE y sus consecuencias; investigaciones sobre Ia posibilidad de migraci6n a partir de diferentes tipos de polfmeros.

ETER DE TETRABROMODIFENILO

El eter de tetrabromodifenilo no se fabrica ni se utiliza. No se dispone de dato:> sobre los aspectos siguientes:

• Efectos en mamfferos de laboratorio y en sistemas de ensayo in vitro • Efectos en el ser humano • Efectos en otros organismos en el laboratorio y en el medio ambiente • Evaluaciones previas por parte de 6rganos internacionales

338 Resumen y evaluacion, conclusiones y recomendaciones

1 Resumen y evaluaci6n

1. 1 ldentificaci6n y propiedades ffsicas y qufmicas

El eter de tetrabromodifenilo comercial esta formado por una mezcla de eteres: 41% de tetra-, 45% de penta- y 7% de hexabromodifenilo y alrededor del 7% de PBDE de estructura desconocida. En funci6n de su estructura qufmica, hay 42 posibles is6meros del eter de tetrabromodifenilo. Practicarnente se carece de datos sobre sus propiedades ffsicas y qufmicas, a excepci6n del logaritmo del coeficiente de reparto n-octanol!agua, que es 5,87-6, 16.

1. 2 Producci6n y aplicaciones

Hay un informe de Ia producci6n (utilizaci6n) de unas 1000 toneladas de TeBDE en el Jap6n en 1987. Nose tiene conocimiento de producci6n alguna en Ia actualidad como eter de tetrabromodifenilo, pero esta presente en el eter de pentabromodifenilo comercial en cantidades que oscilan entre el 24 y el 38%.

1.3 Transporte, distribucion y transformacion en el medio ambiente

En muestras de biota, sedimento y fangos cloacales se han encontrado componentes del TeBDE comercial. Es probable que estos (con cantidades aproximadamente iguales de PeBDE) sean persistentes y bioacumulables. En estudios de pir61isis con TeBDE comercial se puso de manifiesto que a 800 ac se formaban PBDF y PBDD. No se encontraron estos compuestos con mas atomos de bromo.

1.4 Niveles medioambientales y exposicion humana

Se detect6 TeBDE en el sedimento de rfos del Jap6n en concentraciones de 12-31 1-tg/kg de peso seco y en Suecia a niveles de basta 840 ~-tg/kg de perdida por incineraci6n. Tambien se encontr6 TeBDE en fangos cloacales de Suecia a concentraciones de 15 J!g/kg. Los mejillones y peces recogidos en diferentes lugares del Jap6n contenfan TeBDE en concentraciones que oscilaban entre < 0, 1 y 14,6 J.tg de 2,2' ,4,4'-TeBDE/kg de peso seco. En Suecia se

339 EHC 162: Brominated diphenyl ethers

recogieron diferentes tipos de peces en diversos rfos para analizar Ia concentraci6n de 2,2' ,4,4'-TeBDE. Las concentraciones medias variaron entre Ia no detectable ( < 0,1 mg/kg) y 110 mg/kg de grasa. En los anlllisis se puso de manifiesto Ia existencia de por lo menos una fuente local de contaminaci6n en un rfo determinado. Los coregonos, las truchas alpinas y los arenques recogidos en distintos lugares de Suecia en 1986-87 contenfan concentraciones de 15, 400 y 59-450 J,tg de 2,2',4,4'-TeBDE/kg de grasa respectivamente. Los peces recogidos en rfos de Alemania contenfan hasta 1 mg de TeBDE/kg de grasa. En el arenque y en el hfgado de bacalao procedentes de las regiones meridional, central y septentrional del mar del Norte durante el perfodo 1983-89, se encontr6 una tendencia decreciente en la conc~ntraci6n del TeBDE en direcci6n sur-norte. En el arenque se detectaron concentraciones de 8,4-100 J,tg de 2,2' ,4,4' -TeBDE/kg de grasa. En el tejido muscular de aves que se reproducen e invernan en el mar Baltica, el mar del Norte y Spitzbergen se determinaron concentraciones de 80 a 370 J,tg de 2,2',4,4'-TeBDE/kg de grasa. Los quebrantahuesos recogidos en Suecia entre 1982 y 1986 contenfan concentraciones medias de 1800 J,tg/kg de grasa. Se ha indicado que hay una tendencia creciente de las concentraciones de 2,2',4,4'-TeBDE en los sedimentos del mar Baltica, los peces de agua dulce y los huevos de aves marinas de Suecia. En Ia grasa de las focas recogidas en el mar Baltica y en Spitzbergen se determinaron concentraciones de 10-73 JI-g de 2,2' ,4,4'-TeBDE/kg de grasa. El perfil cromatografico del PBDE fue semejante al del Bromkal 70-5. En mezclas de muestras de grasa de focas oceladas y focas grises recogidas en Suecia en 1979-85 se encontraron concentraciones de 47 J,tg y 650 J,tg de 2,2',4,4'­ TeBDE/kg de grasa, respectivamente. Las mezclas de muestras de musculo de mamfferos terrestres, por ejemplo conejos, ratones y renos, recogidas en Suecia en 1985 y 1986 pusieron de manifiesto concentraciones medias de < 2, 0,82 y 0,18 J,tg de 2,2',4,4'-TeBDE/kg de grasa, respectivamente. En cuatro muestras de leche de vaca recogidas en Alemania se encontraron niveles de 2,5-4,5 J,tg de PBDE/kg de grasa, medida

340 Resumen y evaluacion, conclusiones y recomendaciones

como Bromkal 70DE. En la leche de 25 mujeres de Alemania se encontr6 PBDE, como Bromkal 70DE, en concentraciones que oscilaron entre 6,2 y 11, 1 1-1-g/kg de grasa. Una estimaci6n aproximada de la exposici6n a traves del consumo de pescado entre Ia poblaci6n sueca parece indicar una absorci6n diaria de 0,3 1-1-g de TeBDE/persona.

1.5 Efectos en los mamfferos de laboratorio y en los sistemas de ensayo in vitro

No hay datos sobre el propio TeBDE, pero se dispone de datos sobre toxicidad aguda y a corto plazo del PeBDE comercial con un contenido de TeBDE del 41%.

1.6 Cinetica y metabolismo en animales de laboratorio y en el ser humano

Se dispone de muy pocos datos.

1. 7 Efectos en el ser humano

Se carece de datos.

1.8 Efectos en otros organismos de laboratorio y del medio ambiente

Se carece de datos.

2 Conclusiones

2.1 TeBDE

Los componentes del TeBDE comercial (una mezcla de un 41% de 2,2',4,4'-tetra-; 45% de 2,2',4,4',5'-penta-; 7% de hexa-; y 7- 8% de eteres de difenilo polibromados de estructura desconocida) son persistentes y se acumulan en organismos del medio ambiente. El TeBDE, como componente del eter de pentabromodifenilo, se incorpora con profusi6n a polfmeros como aditivo pirorretardante. El contacto de Ia poblaci6n general se produce a traves de productos fabricados con estos polfmeros. No es probable Ia exposici6n por extracci6n a partir de los mismos. Es posible Ia exposici6n humana

341 EHC 162: Brominated diphenyl ethers

al TeBDE, mediante la cadena alimentaria, porque se ha detectado su presencia en organismos del medio ambiente que forman parte de la alimentaci6n humana, como por ejemplo peces, crustaceos, etc. Durante los dos ultimos decenios se han determinado concentraciones crecientes en los peces y las aves de Suecia. Apenas se dispone de informaci6n acerca de la toxicidad/ carcinogenicidad a corto y largo plazo y de estudios de reproducci6n. No se puede determinar el riesgo para la poblaci6n general en funci6n de los datos disponibles. No se dispone de la informaci6n necesaria para poder sacar conclusiones sobre los niveles de exposici6n en el trabajo o los efectos del TeBDE. Tampoco hay datos acerca de la toxicidad del TeBDE comercial para los organismos del medio ambiente.

2. 2 Productos de degradacion

Cuando el TeBDE se calienta a 800 oc se forman PBDF y PBDD. Hay que prestar atenci6n a los posibles peligros relacionados con estos. La exposici6n de la poblaci6n general al PBDF de los polfmeros pirorretardantes con TeBDE probablemente carece de importancia. La incineraci6n con los controles adecuados no produce una emisi6n de cantidades importantes de dioxinas y furanos bromados. Cualquier combusti6n sin control de productos que contienen TeBDE puede dar Iugar a Ia formaci6n de cantidades no cuantificadas de PBDF/PBDD. Un futuro numero de EHC se ocupara de su importancia para el ser humano y el medio ambiente.

3 Recomendaciones

3. 1 Generales

Dada su persistencia en el medio ambiente y Ia acumulaci6n en organismos, se recomienda que no se utilice TeBDE. Sin embargo, si se va a seguir usando hay que tener en cuenta los puntos siguientes:

342 Resumen y evaluacion, conclusiones y recomendaciones

• Se debe proteger de Ia exposici6n a los trabajadores que intervienen en Ia fabricaci6n de TeBDE y de los productos que contienen el compuesto, mediante medidas adecuadas de higiene industrial, vigilancia de la exposici6n en el trabajo y controles tecnicos. • Hay que reducir al mfnimo la exposici6n ambiental mediante el tratamiento adecuado de efluentes y emisiones de las industrias que utilizan el compuesto o sus productos. Se debe controlar Ia eliminaci6n de desechos industriales y de productos de consumo para evitar en lo posible Ia contaminaci6n del medio ambiente con este producto persistente y acumulable, asf como con sus productos de degradaci6n. • La incineraci6n de materiales pirorretardantes con TeBDE s61o se debe realizar en incineradores adecuados que funcionen siempre en condiciones 6ptimas. La quema por otros medios dan\ Iugar a Ia formaci6n de productos de degradaci6n del furano t6xicos.

3. 2 Otros estudios

• Se requiere una vigilancia permanente de sus niveles en el medio ambiente. • Se deben validar metodos de determinaci6n del TeBDE en diversos aglomerantes. • Habida cuenta de que Ia base de datos toxicol6gicos actual no es adecuada para evaluar los peligros del TeBDE comercial para el ser humano y el medio ambiente, si se va a continuar con su uso se deberfan realizar los siguientes estudios: estudios adicionales toxico16gicos. carcinogenicos y ecotoxicol6gicos; nuevas investigaciones sobre Ia formaci6n de PBDF en condiciones de incendios reales; investigaci6n de posibles metodos de reciclaje de polfmeros que contienen TeBDE y sus consecuencias;

343 EHC 162: Brominated diphenyl ethers

investigaciones sobre Ia posibilidad de migraci6n a partir de diferentes tipos de polfmeros.

ETER DE TRIBROMODIFENILO

El eter de tribromodifenilo no se fabrica ni se utiliza. No se dispone de datos sobre los aspectos siguientes: • Transporte, distribuci6n y transformaci6n en el medio ambiente • Cinetica y metabolismo en animales de laboratorio y en el ser humano • Efectos en mamfferos de laboratorio y en sistemas de ensayo in vitro • Efectos en el ser humano • Efectos en otros organismos en el laboratorio y en el medio ambiente • Evaluaciones anteriores por parte de 6rganos internacionales.

1 Resumen y evaluaci6n

No hay una base de datos sobre Ia cual realizar una evaluaci6n.

2 Recomendaciones

Se debe reducir al mfnimo Ia contaminaci6n de los productos comerciales con eter de tribromodifenilo, a fin de evitar Ia del medio ambiente y Ia exposici6n humana. Hay que evitar el uso de los productos comerciales capaces de contaminar el medio ambiente.

344 Resumen y evaluacion, conclusiones y recomendaciones

ETER DE DIBROMODIFENILO

El ~ter de dibromodifenilo no se fabrica ni se utiliza. No se dispone de datos sobre los aspectos siguientes:

• Cin~tica y metabolismo en animales de laboratorio y en el ser humano • Efectos en el ser humano • Efectos en otros organismos en el laboratorio y en el medio ambiente • Evaluaciones anteriores por parte de 6rganos internacionales.

1 Resumen y evaluaci6n

No hay una base de datos sobre la cual realizar una evaluaci6n.

2 Recomendaciones

Se debe reducir al mfnimo la contaminaci6n de los productos comerciales con ~ter de dibromodifenilo, a fin de evitar Ia del medio ambiente y Ia exposici6n humana. Hay que evitar el uso de los productos comerciales capaces de contaminar el medio ambiente.

ETER DE MONOBROMODIFENILO

No se dispone de datos sobre los aspectos siguientes:

• Cin~tica y metabolismo en animales de laboratorio y en el ser humano • Efectos en el ser humano. • Evaluaciones anteriores por parte de 6rganos internacionales.

345 EHC 162: Brominated diphenyl ethers

1 Resumen y evaluaci6n

1. 1 Propiedades ffsicas y quimicas

El eter de monobromodifenilo tiene tres posibles is6meros. El eter de p-bromodifenilo a temperatura ambiente es un lfquido con un punto de ebullici6n de 305-310 °C. Se estima que su solubilidad en agua es de 48 mg/litro. El log del coeficiente de reparto n-octanol/agua es de 4 a 5. La presi6n de vapor a 20 oc es de 0,0015 mm de Hg.

1. 2 Produccion y aplicaciones

El MBDE no se utiliza como pirorretardante. En 1977 apareci6 un informe sobre su producci6n, pero se desconoce su empleo.

1.3 Transporte, distribucion y transformacion en el medio ambiente

La semivida de volatizaci6n a partir del agua es del orden de centenares de dfas. Aunque el MBDE no se degrad6 de manera significativa en un cultivo de siete dfas con microorganismos de las aguas residuales domesticas, se ha informado que en los fangos cloacales activados lo hace en un 95% . En un estudio aislado se puso de manifiesto que una cepa de bacterias del suelo no era capaz de degradar el MBDE como unica fuente de carbono.

1.4 Niveles medioambientales y exposicion humana

Se ha detectado MBDE en muestras de agua superficial recogidas en las cercanfas de zonas industriales de los Estados Unidos, pero no se obtuvieron estos resultados en un estudio semejante realizado en el Jap6n. Se encontr6 asimismo en agua del suelo de un Iugar pr6ximo a una instalaci6n industrial de los Estados Unidos. Tambien se ha detectado en el sedimento acuatico y en Ia biota acuatica de los Estados Unidos.

346 Resumen y evaluacion, conclusiones y recomendaciones

1.5 Cinetica y metabolismo en animales de /aboratorio y en el ser humano

No se dispone de datos.

1. 6 Efectos en mamfferos de laboratorio y en sistemas de ensayo in vitro

El MBDE no es teratogenico, pero se carece de datos sobre su toxicidad aguda, a corto plazo y a largo plazo, y por consiguiente no se puede realizar su evaluaci6n.

1. 7 Efectos en el ser humano

No se dispone de datos.

1.8 Efectos en otros organismos en el Jaboratorio y en el medio ambiente

Se ha informado que Ia CL50 en 96 h para Lepomis macrochirus es de 4,9 mg/litro, con una concentraci6n sin efectos observados de

menos de 2,8 mg/litro. La CL 50 en 48 horas para Ia pulga de agua fue de 0,36 mg/litro, con un NOEC de menos de 0,046 mg/litro.

2 Conclusiones y recomendaciones

El eter de monobromodifenilo no tiene propiedades pirorretardantes. Puede acumularse en los organismos del medio ambiente y se ha detectado en diferentes compartimentos ambientales. Algunas pruebas indican que es biodegradable. La reducida informaci6n de que se dispone impide sacar conclusiones sobre los niveles de exposici6n y los efectos sobre Ia poblaci6n general y los organismos. No existe una base de datos toxicol6gicos que apoye su uso. Se debe evitar todo empleo que provoque la contaminaci6n del medio ambiente.

347

THE ENVIRONMENTAL HEALTH CRITERIA SERIES (continued)

Manganese (No. 17, 1981) 2-Propanol (No. 103, 1990) Mercury (No. 1, 1976)' Propachlor (No. 147, 1993) Mercury - envlronmen1al aspects (No. 86, 1989) Propylene oxide (No. 56, 1985) Mercury, Inorganic (No. 118, 1991) Pyrrolizidine alkaloids (No 80, 1988) 2-Methoxyethanol, 2-ethoxyethanol, and their Quintozene (No. 41, 1984) acetates (No. 115, 1990) Quality management for chemical safety Methylene chloride (No. 32, 1984) testing (No 141, 1992) Methyl ethyl ketone (No. 143, 1992) Radiofrequency and microwaves (No. 16, 1981) Methyl isobutyl ketone (No. 117, 1990) Radlonuclides, selected (No. 25, 1983) Methylmercury (No. 101, 1990) Resmethrlns (No. 92, 1989) Methyl parathion (No. 145, 1992) Selected synthetic organic fibres (No. 151, 1993) Mirex (No. 44, 1984) Selenium (No 58, 1986) Mutagenic and carcinogenic chemicals, guide to Styrene (No. 26, 1983) short-term tests for detecting (No. 51, 1985) Sulfur oxides and suspended particulate Mycotoxins (No. 11, 1979) matter (No. 8, 1979) Mycotoxins, selected: ochratoxins, Tecnazene (No 42, 1984) trichothecenes, ergot (No. 105, 1990) Tetrachloroethylene (No. 31, 1984) Nephrotoxicny associated wnh exposure to Tetradifon (No. 67, 1986) chemicals, principles and methods for the Tetramethrin (No. 98, 1990) assessment of (No. 119, 1991) Thiocarbamate pesticides: a general Neurotoxicny associated wnh exposure to introduction (No. 76, 1988) chemicals, principles and methods for the Tin and organotin compounds (No. 15, 1980) assessment of (No. 60, 1986) Tnanlum (No. 24, 1982) Nickel (No. 108, 1991) Toluene (No. 52, 1986) Nnrates, nnrnes, and N-nnroso compounds Toluene diisocyanates (No. 75, 1987) (No.5, 1978)' Toxicny of chemicals (Part 1), principles and Nnrogen, oxides of (No.4, 1977)' methods for evaluating the (No. 6, 1978) 2-Nnropropane (No. 138, 1992) Toxicokinetic studies, principles of (No. 57, 1986) Noise (No. 12, 1980)' Tributyl phosphate (No. 112, 1991) Organophosphorus insecticides: a general Tributyltin compounds (No. 116, 1990) introduction (No. 63, 1986) Trichlorfon (No. 132, 1992) Paraquat and diquat (No. 39, 1984) 1,1,1-Trichloroethane (No. 136, 1992) Pen1achlorophenol (No. 71, 1987) Trichloroethylene (No. 50, 1985) Permethrin (No. 94, 1990) Tricresyl phosphate (No. 110, 1990) Pesticide residues In food, principles for the Triphenyl phosphate (No. 111, 1991) toxicological assessment of (No. 104, 1990) Ultrasound (No. 22, 1982) Petroleum products, selected (No. 20, 1982) Ultraviolet radiation Phenol (No. 161 , 1994) (No. 14, 1979, 1st edition) d-Phenothrin (No 96, 1990) (No. 160, 1994, 2nd edition) Phosphine and selected me1al phosphides Vanadium (No. 81, 1988) (No. 73, 1988) Vinylidene chloride (No. 100, 1990) Photochemical oxidants (No.7, 1978) Platinum (No. 125, 1991) Polybrominated biphenyls (No 152, 1994) Polychlorinated biphenyls and terphenyls (No. 2, 1976, 1st ednion)' (No. 140, 1992, 2nd ednion) Polychlorinated dibenzo-p-dioxins and dibenzofurans (No. 88, 1989) Progeny, principles for evaluating health risks associated with exposure to chemicals during pregnancy (No 30, 1984) !-Propanol (No. 102, 1990)

• Out of print

To obtain further copies of monographs in this series, please write to the Office of Distribution and Sales, World Health Organization, 1211 Geneva 27, Switzerland (Fax No. 41-22-7880401}